diff --git a/Cargo.toml b/Cargo.toml
index b499eebc..69b35461 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,19 +20,19 @@ chrono = "0.4"
 handlebars = "0.29"
 serde = "1.0"
 serde_derive = "1.0"
-error-chain = "0.11.0"
+error-chain = "0.11"
 serde_json = "1.0"
 pulldown-cmark = "0.1"
 lazy_static = "1.0"
 log = "0.4"
 env_logger = "0.5.0-rc.1"
 toml = "0.4"
-memchr = "2.0.1"
+memchr = "2.0"
 open = "1.1"
 regex = "0.2.1"
 tempdir = "0.3.4"
-itertools = "0.7.4"
-shlex = "0.1.1"
+itertools = "0.7"
+shlex = "0.1"
 toml-query = "0.6"
 
 # Watch feature
@@ -66,3 +66,5 @@ doc = false
 name = "mdbook"
 path = "src/bin/mdbook.rs"
 
+[workspace]
+members = ["book-example/src/for_developers/mdbook-wordcount"]
diff --git a/book-example/book.toml b/book-example/book.toml
index 1c2e9699..df1ed5c5 100644
--- a/book-example/book.toml
+++ b/book-example/book.toml
@@ -1,7 +1,7 @@
 [book]
 title = "mdBook Documentation"
 description = "Create book from markdown files. Like Gitbook but implemented in Rust"
-author = "Mathieu David"
+authors = ["Mathieu David", "Michael-F-Bryan"]
 
 [output.html]
 mathjax-support = true
diff --git a/book-example/src/SUMMARY.md b/book-example/src/SUMMARY.md
index 078eef90..aba9ab5d 100644
--- a/book-example/src/SUMMARY.md
+++ b/book-example/src/SUMMARY.md
@@ -16,6 +16,8 @@
         - [Editor](format/theme/editor.md)
     - [MathJax Support](format/mathjax.md)
     - [Rust code specific features](format/rust.md)
-- [For Developers](lib/index.md)
+- [For Developers](for_developers/index.md)
+    - [Preprocessors](for_developers/preprocessors.md)
+    - [Alternate Backends](for_developers/backends.md)
 -----------
 [Contributors](misc/contributors.md)
diff --git a/book-example/src/for_developers/backends.md b/book-example/src/for_developers/backends.md
new file mode 100644
index 00000000..e09018f4
--- /dev/null
+++ b/book-example/src/for_developers/backends.md
@@ -0,0 +1,352 @@
+# Alternate Backends
+
+A "backend" is simply a program which `mdbook` will invoke during the book 
+rendering process. This program is passed a JSON representation of the book and
+configuration information via `stdin`. Once the backend receives this 
+information it is free to do whatever it wants.
+
+There are already several alternate backends on GitHub which can be used as a 
+rough example of how this is accomplished in practice.
+
+- [mdbook-linkcheck] - a simple program for verifying the book doesn't contain
+  any broken links
+- [mdbook-epub] - an EPUB renderer
+- [mdbook-test] - a program to run the book's contents through [rust-skeptic] to
+  verify everything compiles and runs correctly (similar to `rustdoc --test`)
+
+This page will step you through creating your own alternate backend in the form
+of a simple word counting program. Although it will be written in Rust, there's
+no reason why it couldn't be accomplished using something like Python or Ruby.
+
+
+## Setting Up
+
+First you'll want to create a new binary program and add `mdbook` as a 
+dependency.
+
+```
+$ cargo new --bin mdbook-wordcount
+$ cd mdbook-wordcount 
+$ cargo add mdbook
+```
+
+When our `mdbook-wordcount` plugin is invoked, `mdbook` will send it a JSON 
+version of [`RenderContext`] via our plugin's `stdin`. For convenience, there's 
+a [`RenderContext::from_json()`] constructor which will load a `RenderContext`.
+
+This is all the boilerplate necessary for our backend to load the book.
+
+```rust
+// src/main.rs
+extern crate mdbook;
+
+use std::io;
+use mdbook::renderer::RenderContext;
+
+fn main() {
+    let mut stdin = io::stdin();
+    let ctx = RenderContext::from_json(&mut stdin).unwrap();
+}
+```
+
+> **Note:** The `RenderContext` contains a `version` field. This lets backends 
+  figure out whether they are compatible with the version of `mdbook` it's being
+  called by. This `version` comes directly from the corresponding field in 
+  `mdbook`'s `Cargo.toml`. 
+  
+  It is recommended that backends use the [`semver`] crate to inspect this field
+  and emit a warning if there may be a compatibility issue.
+
+
+## Inspecting the Book
+
+Now our backend has a copy of the book, lets count how many words are in each 
+chapter!
+
+Because the `RenderContext` contains a [`Book`] field (`book`), and a `Book` has
+the [`Book::iter()`] method for iterating over all items in a `Book`, this step
+turns out to be just as easy as the first.
+
+```rust
+
+fn main() {
+    let mut stdin = io::stdin();
+    let ctx = RenderContext::from_json(&mut stdin).unwrap();
+
+    for item in ctx.book.iter() {
+        if let BookItem::Chapter(ref ch) = *item {
+            let num_words = count_words(ch);
+            println!("{}: {}", ch.name, num_words);
+        }
+    }
+}
+
+fn count_words(ch: &Chapter) -> usize {
+    ch.content.split_whitespace().count()
+}
+```
+
+
+## Enabling the Backend
+
+Now we've got the basics running, we want to actually use it. First, install
+the program.
+
+```
+$ cargo install
+```
+
+Then `cd` to the particular book you'd like to count the words of and update its
+`book.toml` file. 
+
+```diff
+  [book]
+  title = "mdBook Documentation"
+  description = "Create book from markdown files. Like Gitbook but implemented in Rust"
+  authors = ["Mathieu David", "Michael-F-Bryan"]
+
++ [output.html]
+
++ [output.wordcount]
+```
+
+When it loads a book into memory, `mdbook` will inspect your `book.toml` file 
+to try and figure out which backends to use by looking for all `output.*`
+tables. If none are provided it'll fall back to using the default HTML
+renderer. 
+
+Notably, this means if you want to add your own custom backend you'll also
+need to make sure to add the HTML backend, even if its tabke just stays empty.
+
+Now you just need to build your book like normal, and everything should *Just 
+Work*.
+
+```
+$ mdbook build
+...
+2018-01-16 07:31:15 [INFO] (mdbook::renderer): Invoking the "mdbook-wordcount" renderer
+mdBook: 126
+Command Line Tool: 224
+init: 283
+build: 145
+watch: 146
+serve: 292
+test: 139
+Format: 30
+SUMMARY.md: 259
+Configuration: 784
+Theme: 304
+index.hbs: 447
+Syntax highlighting: 314
+MathJax Support: 153
+Rust code specific features: 148
+For Developers: 788
+Alternate Backends: 710
+Contributors: 85
+```
+
+The reason we didn't need to specify the full name/path of our `wordcount` 
+backend is because `mdbook` will try to *infer* the program's name via 
+convention. The executable for the `foo` backend is typically called 
+`mdbook-foo`, with an associated `[output.foo]` entry in the `book.toml`. To
+explicitly tell `mdbook` what command to invoke (it may require command line 
+arguments or be an interpreted script), you can use the `command` field.
+
+```diff
+  [book]
+  title = "mdBook Documentation"
+  description = "Create book from markdown files. Like Gitbook but implemented in Rust"
+  authors = ["Mathieu David", "Michael-F-Bryan"]
+
+  [output.html]
+
+  [output.wordcount]
++ command = "python /path/to/wordcount.py"
+```
+
+
+## Configuration
+
+Now imagine you don't want to count the number of words on a particular chapter
+(it might be generated text/code, etc). The canonical way to do this is via
+the usual `book.toml` configuration file by adding items to your `[output.foo]` 
+table. 
+
+The `Config` can be treated roughly as a nested hashmap which lets you call
+methods like `get()` to access the config's contents, with a
+`get_deserialized()` convenience method for retrieving a value and
+automatically deserializing to some arbitrary type `T`.
+
+To implement this, we'll create our own serializable `WordcountConfig` struct 
+which will encapsulate all configuration for this backend.
+
+First add `serde` and `serde_derive` to your `Cargo.toml`,
+
+```
+$ cargo add serde serde_derive
+```
+
+And then you can create the config struct,
+
+```rust
+extern crate serde;
+#[macro_use]
+extern crate serde_derive;
+
+...
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+#[serde(default, rename_all = "kebab-case")]
+pub struct WordcountConfig {
+  pub ignores: Vec<String>,
+}
+```
+
+Now we just need to deserialize the `WordcountConfig` from our `RenderContext`
+and then add a check to make sure we skip ignored chapters.
+
+```diff
+  fn main() {
+      let mut stdin = io::stdin();
+      let ctx = RenderContext::from_json(&mut stdin).unwrap();
++     let cfg: WordcountConfig = ctx.config
++         .get_deserialized("output.wordcount")
++         .unwrap_or_default();
+  
+      for item in ctx.book.iter() {
+          if let BookItem::Chapter(ref ch) = *item {
++             if cfg.ignores.contains(&ch.name) {
++                 continue;
++             }
++ 
+              let num_words = count_words(ch);
+              println!("{}: {}", ch.name, num_words);
+          }
+      }
+  }
+```
+
+
+## Output and Signalling Failure
+
+While it's nice to print word counts to the terminal when a book is built, it 
+might also be a good idea to output them to a file somewhere. `mdbook` tells a
+backend where it should place any generated output via the `destination` field
+in [`RenderContext`].
+
+```diff
++ use std::fs::{self, File};
++ use std::io::{self, Write};
+- use std::io;
+  use mdbook::renderer::RenderContext;
+  use mdbook::book::{BookItem, Chapter};
+  
+  fn main() {
+    ...
+  
++     let _ = fs::create_dir_all(&ctx.destination);
++     let mut f = File::create(ctx.destination.join("wordcounts.txt")).unwrap();
++ 
+      for item in ctx.book.iter() {
+          if let BookItem::Chapter(ref ch) = *item {
+              ...
+  
+              let num_words = count_words(ch);
+              println!("{}: {}", ch.name, num_words);
++             writeln!(f, "{}: {}", ch.name, num_words).unwrap();
+          }
+      }
+  }
+```
+
+> **Note:** There is no guarantee that the destination directory exists or is
+> empty (`mdbook` may leave the previous contents to let backends do caching),
+> so it's always a good idea to create it with `fs::create_dir_all()`.
+
+There's always the possibility that an error will occur while processing a book
+(just look at all the `unwrap()`'s we've written already), so `mdbook` will 
+interpret a non-zero exit code as a rendering failure.
+
+For example, if we wanted to make sure all chapters have an *even* number of
+words, erroring out if an odd number is encountered, then you may do something
+like this:
+
+```diff
++ use std::process;
+  ...
+
+  fn main() {
+      ...
+  
+      for item in ctx.book.iter() {
+          if let BookItem::Chapter(ref ch) = *item {
+              ...
+  
+              let num_words = count_words(ch);
+              println!("{}: {}", ch.name, num_words);
+              writeln!(f, "{}: {}", ch.name, num_words).unwrap();
+
++             if cfg.deny_odds && num_words % 2 == 1 {
++               eprintln!("{} has an odd number of words!", ch.name);
++               process::exit(1);
+              }
+          }
+      }
+  }
+
+  #[derive(Debug, Default, Serialize, Deserialize)]
+  #[serde(default, rename_all = "kebab-case")]
+  pub struct WordcountConfig {
+      pub ignores: Vec<String>,
++     pub deny_odds: bool,
+  }
+```
+
+Now, if we reinstall the backend and build a book,
+
+```
+$ cargo install --force
+$ mdbook build /path/to/book
+...
+2018-01-16 21:21:39 [INFO] (mdbook::renderer): Invoking the "wordcount" renderer
+mdBook: 126
+Command Line Tool: 224
+init: 283
+init has an odd number of words!
+2018-01-16 21:21:39 [ERROR] (mdbook::renderer): Renderer exited with non-zero return code.
+2018-01-16 21:21:39 [ERROR] (mdbook::utils): Error: Rendering failed
+2018-01-16 21:21:39 [ERROR] (mdbook::utils): 	Caused By: The "mdbook-wordcount" renderer failed
+```
+
+As you've probably already noticed, output from the plugin's subprocess is
+immediately passed through to the user. It is encouraged for plugins to
+follow the "rule of silence" and only generate output when necessary (e.g. an
+error in generation or a warning).
+
+All environment variables are passed through to the backend, allowing you to
+use the usual `RUST_LOG` to control logging verbosity.
+
+
+## Wrapping Up
+
+Although contrived, hopefully this example was enough to show how you'd create
+an alternate backend for `mdbook`. If you feel it's missing something, don't 
+hesitate to create an issue in the [issue tracker] so we can improve the user
+guide.
+
+The existing backends mentioned towards the start of this chapter should serve
+as a good example of how it's done in real life, so feel free to skim through 
+the source code or ask questions.
+
+
+[mdbook-linkcheck]: https://github.com/Michael-F-Bryan/mdbook-linkcheck
+[mdbook-epub]: https://github.com/Michael-F-Bryan/mdbook-epub
+[mdbook-test]: https://github.com/Michael-F-Bryan/mdbook-test
+[rust-skeptic]: https://github.com/budziq/rust-skeptic
+[`RenderContext`]: http://rust-lang-nursery.github.io/mdBook/mdbook/renderer/struct.RenderContext.html
+[`RenderContext::from_json()`]: http://rust-lang-nursery.github.io/mdBook/mdbook/renderer/struct.RenderContext.html#method.from_json
+[`semver`]: https://crates.io/crates/semver
+[`Book`]: http://rust-lang-nursery.github.io/mdBook/mdbook/book/struct.Book.html
+[`Book::iter()`]: http://rust-lang-nursery.github.io/mdBook/mdbook/book/struct.Book.html#method.iter
+[`Config`]: http://rust-lang-nursery.github.io/mdBook/mdbook/config/struct.Config.html 
+[issue tracker]: https://github.com/rust-lang-nursery/mdBook/issues
\ No newline at end of file
diff --git a/book-example/src/for_developers/index.md b/book-example/src/for_developers/index.md
new file mode 100644
index 00000000..3a193a25
--- /dev/null
+++ b/book-example/src/for_developers/index.md
@@ -0,0 +1,46 @@
+# For Developers
+
+While `mdbook` is mainly used as a command line tool, you can also import the 
+underlying library directly and use that to manage a book. It also has a fairly
+flexible plugin mechanism, allowing you to create your own custom tooling and 
+consumers (often referred to as *backends*) if you need to do some analysis of
+the book or render it in a different format.
+
+The *For Developers* chapters are here to show you the more advanced usage of 
+`mdbook`.
+
+The two main ways a developer can hook into the book's build process is via,
+
+- [Preprocessors](for_developers/preprocessors.html)
+- [Alternate Backends](for_developers/backends.html)
+
+
+## The Build Process
+
+The process of rendering a book project goes through several steps.
+
+1. Load the book 
+    - Parse the `book.toml`, falling back to the default `Config` if it doesn't
+       exist.
+    - Load the book chapters into memory
+    - Discover which preprocessors/backends should be used
+2. Run the preprocessors
+3. Call each backend in turn
+
+
+## Using `mdbook` as a Library
+
+The `mdbook` binary is just a wrapper around the `mdbook` crate, exposing its
+functionality as a command-line program. As such it is quite easy to create your
+own programs which use `mdbook` internally, adding your own functionality (e.g. 
+a custom preprocessor) or tweaking the build process.
+
+The easiest way to find out how to use the `mdbook` crate is by looking at the
+[API Docs]. The top level documentation explains how one would use the 
+[`MDBook`] type to load and build a book, while the [config] module gives a good
+explanation on the configuration system.
+
+
+[`MDBook`]: http://rust-lang-nursery.github.io/mdBook/mdbook/book/struct.MDBook.html
+[API Docs]: http://rust-lang-nursery.github.io/mdBook/mdbook/
+[config]: file:///home/michael/Documents/forks/mdBook/target/doc/mdbook/config/index.html
\ No newline at end of file
diff --git a/book-example/src/for_developers/mdbook-wordcount/Cargo.toml b/book-example/src/for_developers/mdbook-wordcount/Cargo.toml
new file mode 100644
index 00000000..55962233
--- /dev/null
+++ b/book-example/src/for_developers/mdbook-wordcount/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "mdbook-wordcount"
+version = "0.1.0"
+authors = ["Michael Bryan <michaelfbryan@gmail.com>"]
+workspace = "../../../.."
+
+[dependencies]
+mdbook = { path = "../../../.." }
+serde = "1.0"
+serde_derive = "1.0"
diff --git a/book-example/src/for_developers/mdbook-wordcount/src/main.rs b/book-example/src/for_developers/mdbook-wordcount/src/main.rs
new file mode 100644
index 00000000..607338dd
--- /dev/null
+++ b/book-example/src/for_developers/mdbook-wordcount/src/main.rs
@@ -0,0 +1,49 @@
+extern crate mdbook;
+extern crate serde;
+#[macro_use]
+extern crate serde_derive;
+
+use std::process;
+use std::fs::{self, File};
+use std::io::{self, Write};
+use mdbook::renderer::RenderContext;
+use mdbook::book::{BookItem, Chapter};
+
+fn main() {
+    let mut stdin = io::stdin();
+    let ctx = RenderContext::from_json(&mut stdin).unwrap();
+    let cfg: WordcountConfig = ctx.config
+        .get_deserialized("output.wordcount")
+        .unwrap_or_default();
+
+    let _ = fs::create_dir_all(&ctx.destination);
+    let mut f = File::create(ctx.destination.join("wordcounts.txt")).unwrap();
+
+    for item in ctx.book.iter() {
+        if let BookItem::Chapter(ref ch) = *item {
+            if cfg.ignores.contains(&ch.name) {
+                continue;
+            }
+
+            let num_words = count_words(ch);
+            println!("{}: {}", ch.name, num_words);
+            writeln!(f, "{}: {}", ch.name, num_words).unwrap();
+
+            if cfg.deny_odds && num_words % 2 == 1 {
+                eprintln!("{} has an odd number of words!", ch.name);
+                process::exit(1);
+            }
+        }
+    }
+}
+
+fn count_words(ch: &Chapter) -> usize {
+    ch.content.split_whitespace().count()
+}
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+#[serde(default, rename_all = "kebab-case")]
+pub struct WordcountConfig {
+    pub ignores: Vec<String>,
+    pub deny_odds: bool,
+}
diff --git a/book-example/src/for_developers/preprocessors.md b/book-example/src/for_developers/preprocessors.md
new file mode 100644
index 00000000..4d952902
--- /dev/null
+++ b/book-example/src/for_developers/preprocessors.md
@@ -0,0 +1,32 @@
+# Preprocessors
+
+A *preprocessor* is simply a bit of code which gets run immediately after the
+book is loaded and before it gets rendered, allowing you to update and mutate
+the book. Possible use cases are:
+
+- Creating custom helpers like `{{#include /path/to/file.md}}`
+- Updating links so `[some chapter](some_chapter.md)` is automatically changed 
+  to `[some chapter](some_chapter.html)` for the HTML renderer
+- Substituting in latex-style expressions (`$$ \frac{1}{3} $$`) with their 
+  mathjax equivalents
+
+
+## Implementing a Preprocessor 
+
+A preprocessor is represented by the `Preprocessor` trait.
+
+```rust
+pub trait Preprocessor {
+    fn name(&self) -> &str;
+    fn run(&self, ctx: &PreprocessorContext, book: &mut Book) -> Result<()>;
+}
+```
+
+Where the `PreprocessorContext` is defined as
+
+```rust
+pub struct PreprocessorContext {
+    pub root: PathBuf,
+    pub config: Config,
+}
+```
\ No newline at end of file
diff --git a/book-example/src/format/rust.md b/book-example/src/format/rust.md
index d684dc75..3b84534a 100644
--- a/book-example/src/format/rust.md
+++ b/book-example/src/format/rust.md
@@ -35,8 +35,10 @@ With the following syntax, you can insert runnable Rust files into your book:
 
 The path to the Rust file has to be relative from the current source file.
 
-When play is clicked, the code snippet will be send to the [Rust Playpen]() to be compiled and run. The result is send back and displayed directly underneath the code.
+When play is clicked, the code snippet will be send to the [Rust Playpen] to be compiled and run. The result is send back and displayed directly underneath the code.
 
 Here is what a rendered code snippet looks like:
 
 {{#playpen example.rs}}
+
+[Rust Playpen]: https://play.rust-lang.org/
\ No newline at end of file
diff --git a/book-example/src/lib/index.md b/book-example/src/lib/index.md
deleted file mode 100644
index 23b96ec7..00000000
--- a/book-example/src/lib/index.md
+++ /dev/null
@@ -1,176 +0,0 @@
-# For Developers
-
-While `mdbook` is mainly used as a command line tool, you can also import the 
-underlying library directly and use that to manage a book. 
-
-- Creating custom backends 
-- Automatically generating and reloading a book on the fly 
-- Integration with existing projects
-
-The best source for examples on using the `mdbook` crate from your own Rust 
-programs is the [API Docs].
-
-
-## Configuration
-
-The mechanism for using alternative backends is very simple, you add an extra
-table to your `book.toml` and the `MDBook::load()` function will automatically 
-detect the backends being used.
-
-For example, if you wanted to use a hypothetical `latex` backend you would add
-an empty `output.latex` table to `book.toml`.
-
-```toml
-# book.toml
-
-[book]
-...
-
-[output.latex]
-``` 
-
-And then during the rendering stage `mdbook` will run the `mdbook-latex`
-program, piping it a JSON serialized [RenderContext] via stdin.
-
-You can set the command used via the `command` key.
-
-```toml
-# book.toml
-
-[book]
-...
-
-[output.latex]
-command = "python3 my_plugin.py"
-``` 
-
-If no backend is supplied (i.e. there are no `output.*` tables), `mdbook` will 
-fall back to the `html` backend.
-
-### The `Config` Struct
-
-If you are developing a plugin or alternate backend then whenever your code is
-called you will almost certainly be passed a reference to the book's `Config`. 
-This can be treated roughly as a nested hashmap which lets you call methods like
-`get()` and `get_mut()` to get access to the config's contents.
-
-By convention, plugin developers will have their settings as a subtable inside
-`plugins` (e.g. a link checker would put its settings in `plugins.link_check`) 
-and backends should put their configuration under `output`, like the HTML 
-renderer does in the previous examples.
-
-As an example, some hypothetical `random` renderer would typically want to load
-its settings from the `Config` at the very start of its rendering process. The
-author can take advantage of serde to deserialize the generic `toml::Value` 
-object retrieved from `Config` into a struct specific to its use case.
-
-```rust
-extern crate serde;
-#[macro_use]
-extern crate serde_derive;
-extern crate toml;
-extern crate mdbook;
-
-use toml::Value;
-use mdbook::config::Config;
-
-#[derive(Debug, Deserialize, PartialEq)]
-struct RandomOutput {
-    foo: u32,
-    bar: String,
-    baz: Vec<bool>,
-}
-
-# fn run() -> Result<(), Box<::std::error::Error>> {
-let src = r#"
-[output.random]
-foo = 5
-bar = "Hello World"
-baz = [true, true, false]
-"#;
-
-let book_config = Config::from_str(src)?; // usually passed in via the RenderContext
-let random = book_config.get("output.random")
-  .cloned()
-  .ok_or("output.random not found")?;
-let got: RandomOutput = random.try_into()?; 
-
-let should_be = RandomOutput {
-  foo: 5,
-  bar: "Hello World".to_string(),
-  baz: vec![true, true, false]
-};
-
-assert_eq!(got, should_be);
-
-let baz: Vec<bool> = book_config.get_deserialized("output.random.baz")?;
-println!("{:?}", baz); // prints [true, true, false]
-
-// do something interesting with baz
-# Ok(())
-# }
-# fn main() { run().unwrap() }
-```
-
-
-## Render Context
-
-The `RenderContext` encapsulates all the information a backend needs to know
-in order to generate output. Its Rust definition looks something like this:
-
-```rust
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
-pub struct RenderContext {
-    pub version: String,
-    pub root: PathBuf,
-    pub book: Book,
-    pub config: Config,
-    pub destination: PathBuf,
-}
-```
-
-A backend will receive the `RenderContext` via `stdin` as one big JSON blob. If
-possible, it is recommended to import the `mdbook` crate and use the 
-`RenderContext::from_json()` method. This way you should always be able to 
-deserialize the `RenderContext`, and as a bonus will also have access to the 
-methods already defined on the underlying types.
-
-Although backends are told the book's root directory on disk, it is *strongly
-discouraged* to load chapter content from the filesystem. The `root` key is
-provided as an escape hatch for certain plugins which may load additional,
-non-markdown, files.
-
-
-## Output Directory
-
-To make things more deterministic, a backend will be told where it should place
-its generated artefacts.
-
-The general algorithm for deciding the output directory goes something like 
-this:
-
-- If there is only one backend:
-    - `destination` is `config.build.build_dir` (usually `book/`)
-- Otherwise:
-    - `destination` is `config.build.build_dir` joined with the backend's name
-      (e.g. `build/latex/` for the "latex" backend)
-
-
-## Output and Signalling Failure
-
-To signal that the plugin failed it just needs to exit with a non-zero return 
-code. 
-
-All output from the plugin's subprocess is immediately passed through to the
-user, so it is encouraged for plugins to follow the ["rule of silence"] and
-by default only tell the user about things they directly need to respond to
-(e.g. an error in generation or a warning). 
-
-This "silent by default" behaviour can be overridden via the `RUST_LOG`
-environment variable (which `mdbook` will pass through to the backend if set)
-as is typical with Rust applications.
-
-
-[API Docs]: https://docs.rs/mdbook
-[RenderContext]: https://docs.rs/mdbook/*/mdbook/renderer/struct.RenderContext.html
-["rule of silence"]: http://www.linfo.org/rule_of_silence.html
\ No newline at end of file
diff --git a/ci/script.sh b/ci/script.sh
index c1e10bf4..f07c4451 100644
--- a/ci/script.sh
+++ b/ci/script.sh
@@ -2,10 +2,9 @@
 
 set -ex
 
-# TODO This is the "test phase", tweak it as you see fit
 main() {
-    cross build --target $TARGET
-    cross build --target $TARGET --release
+    cross build --target $TARGET --all
+    cross build --target $TARGET --all --release
 
     if [ ! -z $DISABLE_TESTS ]; then
         return
diff --git a/src/book/mod.rs b/src/book/mod.rs
index 4666e271..0a0fe681 100644
--- a/src/book/mod.rs
+++ b/src/book/mod.rs
@@ -5,8 +5,6 @@
 //!
 //! [1]: ../index.html
 
-#![deny(missing_docs)]
-
 mod summary;
 mod book;
 mod init;
@@ -38,9 +36,6 @@ pub struct MDBook {
     pub book: Book,
     renderers: Vec<Box<Renderer>>,
 
-    /// The URL used for live reloading when serving up the book.
-    pub livereload: Option<String>,
-
     /// List of pre-processors to be run on the book
     preprocessors: Vec<Box<Preprocessor>>
 }
@@ -85,7 +80,6 @@ impl MDBook {
 
         let src_dir = root.join(&config.book.src);
         let book = book::load_book(&src_dir, &config.build)?;
-        let livereload = None;
 
         let renderers = determine_renderers(&config);
         let preprocessors = determine_preprocessors(&config)?;
@@ -95,7 +89,6 @@ impl MDBook {
             config,
             book,
             renderers,
-            livereload,
             preprocessors,
         })
     }
diff --git a/src/config.rs b/src/config.rs
index e74f1917..5d252b17 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,4 +1,54 @@
 //! Mdbook's configuration system.
+//! 
+//! The main entrypoint of the `config` module is the `Config` struct. This acts
+//! essentially as a bag of configuration information, with a couple
+//! pre-determined tables (`BookConfig` and `BuildConfig`) as well as support 
+//! for arbitrary data which is exposed to plugins and alternate backends.
+//! 
+//! 
+//! # Examples
+//! 
+//! ```rust
+//! # extern crate mdbook;
+//! # use mdbook::errors::*;
+//! # extern crate toml;
+//! use std::path::PathBuf;
+//! use mdbook::Config;
+//! use toml::Value;
+//! 
+//! # fn run() -> Result<()> {
+//! let src = r#"
+//! [book]
+//! title = "My Book"
+//! authors = ["Michael-F-Bryan"]
+//! 
+//! [build]
+//! src = "out"
+//! 
+//! [other-table.foo]
+//! bar = 123
+//! "#;
+//! 
+//! // load the `Config` from a toml string
+//! let mut cfg = Config::from_str(src)?;
+//! 
+//! // retrieve a nested value
+//! let bar = cfg.get("other-table.foo.bar").cloned();
+//! assert_eq!(bar, Some(Value::Integer(123)));
+//! 
+//! // Set the `output.html.theme` directory
+//! assert!(cfg.get("output.html").is_none());
+//! cfg.set("output.html.theme", "./themes");
+//! 
+//! // then load it again, automatically deserializing to a `PathBuf`.
+//! let got: PathBuf = cfg.get_deserialized("output.html.theme")?;
+//! assert_eq!(got, PathBuf::from("./themes"));
+//! # Ok(())
+//! # }
+//! # fn main() { run().unwrap() }
+//! ```
+
+#![deny(missing_docs)]
 
 use std::path::{Path, PathBuf};
 use std::fs::File;
@@ -14,11 +64,13 @@ use serde_json;
 
 use errors::*;
 
-/// The overall configuration object for MDBook.
+/// The overall configuration object for MDBook, essentially an in-memory
+/// representation of `book.toml`.
 #[derive(Debug, Clone, PartialEq)]
 pub struct Config {
     /// Metadata about the book.
     pub book: BookConfig,
+    /// Information about the build environment.
     pub build: BuildConfig,
     rest: Value,
 }
@@ -344,15 +396,24 @@ impl Default for BuildConfig {
     }
 }
 
+/// Configuration for the HTML renderer.
 #[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
 pub struct HtmlConfig {
+    /// The theme directory, if specified.
     pub theme: Option<PathBuf>,
+    /// Use "smart quotes" instead of the usual `"` character.
     pub curly_quotes: bool,
+    /// Should mathjax be enabled?
     pub mathjax_support: bool,
+    /// An optional google analytics code.
     pub google_analytics: Option<String>,
+    /// Additional CSS stylesheets to include in the rendered page's `<head>`.
     pub additional_css: Vec<PathBuf>,
+    /// Additional JS scripts to include at the bottom of the rendered page's 
+    /// `<body>`.
     pub additional_js: Vec<PathBuf>,
+    /// Playpen settings.
     pub playpen: Playpen,
     /// This is used as a bit of a workaround for the `mdbook serve` command.
     /// Basically, because you set the websocket port from the command line, the
@@ -362,6 +423,7 @@ pub struct HtmlConfig {
     /// This config item *should not be edited* by the end user.
     #[doc(hidden)]
     pub livereload_url: Option<String>,
+    /// Should section labels be rendered?
     pub no_section_label: bool,
 }
 
@@ -369,7 +431,11 @@ pub struct HtmlConfig {
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
 pub struct Playpen {
+    /// The path to the editor to use. Defaults to the [Ace Editor].
+    /// 
+    /// [Ace Editor]: https://ace.c9.io/
     pub editor: PathBuf,
+    /// Should playpen snippets be editable? Defaults to `false`.
     pub editable: bool,
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 08c4c37e..559cec30 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,7 +12,7 @@
 //! - Integrate mdbook in a current project
 //! - Extend the capabilities of mdBook
 //! - Do some processing or test before building your book
-//! - Write a new Renderer
+//! - Accessing the public API to help create a new Renderer
 //! - ...
 //!
 //! # Examples
@@ -50,48 +50,30 @@
 //! md.build().expect("Building failed");
 //! ```
 //!
-//! ## Implementing a new Renderer
+//! ## Implementing a new Backend
 //!
-//! If you want to create a new renderer for mdBook, the only thing you have to
-//! do is to implement the [Renderer](renderer/renderer/trait.Renderer.html)
-//! trait.
-//!
-//! And then you can swap in your renderer like this:
-//!
-//! ```no_run
-//! # extern crate mdbook;
-//! #
-//! # use mdbook::MDBook;
-//! # use mdbook::renderer::HtmlHandlebars;
-//! #
-//! # #[allow(unused_variables)]
-//! # fn main() {
-//! #   let your_renderer = HtmlHandlebars::new();
-//! #
-//! let mut book = MDBook::load("my-book").unwrap();
-//! book.with_renderer(your_renderer);
-//! # }
-//! ```
-//!
-//! If you make a renderer, you get the book constructed in form of
-//! `Vec<BookItems>` and you get ! the book config in a `BookConfig` struct.
-//!
-//! It's your responsability to create the necessary files in the correct
-//! directories.
-//!
-//! ## utils
-//!
-//! I have regrouped some useful functions in the [utils](utils/index.html)
-//! module, like the following function [`utils::fs::create_file(path:
-//! &Path)`](utils/fs/fn.create_file.html).
-//!
-//! This function creates a file and returns it. But before creating the file
-//! it checks every directory in the path to see if it exists, and if it does
-//! not it will be created.
-//!
-//! Make sure to take a look at it.
+//! `mdbook` has a fairly flexible mechanism for creating additional backends 
+//! for your book. The general idea is you'll add an extra table in the book's
+//! `book.toml` which specifies an executable to be invoked by `mdbook`. This
+//! executable will then be called during a build, with an in-memory 
+//! representation ([`RenderContext`]) of the book being passed to the
+//! subprocess via `stdin`. 
+//! 
+//! The [`RenderContext`] gives the backend access to the contents of 
+//! `book.toml` and lets it know which directory all generated artefacts should
+//! be placed in. For a much more in-depth explanation, consult the [relevant
+//! chapter] in the *For Developers* section of the user guide.
+//! 
+//! To make creating a backend easier, the `mdbook` crate can be imported 
+//! directly, making deserializing the `RenderContext` easy and giving you 
+//! access to the various methods for working with the [`Config`].
 //!
 //! [user guide]: https://rust-lang-nursery.github.io/mdBook/
+//! [`RenderContext`]: renderer/struct.RenderContext.html
+//! [relevant chapter]: https://rust-lang-nursery.github.io/mdBook/for_developers/backends.html
+//! [`Config`]: config/struct.Config.html
+
+#![deny(missing_docs)]
 
 #[macro_use]
 extern crate error_chain;
@@ -128,6 +110,7 @@ pub mod utils;
 pub use book::MDBook;
 pub use book::BookItem;
 pub use renderer::Renderer;
+pub use config::Config;
 
 /// The error types used through out this crate.
 pub mod errors {
@@ -135,27 +118,30 @@ pub mod errors {
 
     error_chain!{
         foreign_links {
-            Io(::std::io::Error);
-            HandlebarsRender(::handlebars::RenderError);
-            HandlebarsTemplate(Box<::handlebars::TemplateError>);
-            Utf8(::std::string::FromUtf8Error);
+            Io(::std::io::Error) #[doc = "A wrapper around `std::io::Error`"];
+            HandlebarsRender(::handlebars::RenderError) #[doc = "Handlebars rendering failed"];
+            HandlebarsTemplate(Box<::handlebars::TemplateError>) #[doc = "Unable to parse the template"];
+            Utf8(::std::string::FromUtf8Error) #[doc = "Invalid UTF-8"];
         }
 
         links {
-            TomlQuery(::toml_query::error::Error, ::toml_query::error::ErrorKind);
+            TomlQuery(::toml_query::error::Error, ::toml_query::error::ErrorKind) #[doc = "A TomlQuery error"];
         }
 
         errors {
+            /// A subprocess exited with an unsuccessful return code.
             Subprocess(message: String, output: ::std::process::Output) {
                 description("A subprocess failed")
                 display("{}: {}", message, String::from_utf8_lossy(&output.stdout))
             }
 
+            /// An error was encountered while parsing the `SUMMARY.md` file.
             ParseError(line: usize, col: usize, message: String) {
                 description("A SUMMARY.md parsing error")
                 display("Error at line {}, column {}: {}", line, col, message)
             }
 
+            /// The user tried to use a reserved filename.
             ReservedFilenameError(filename: PathBuf) {
                 description("Reserved Filename")
                 display("{} is reserved for internal use", filename.display())
diff --git a/src/preprocess/links.rs b/src/preprocess/links.rs
index c3cab8bf..aacf295f 100644
--- a/src/preprocess/links.rs
+++ b/src/preprocess/links.rs
@@ -10,9 +10,12 @@ use book::{Book, BookItem};
 
 const ESCAPE_CHAR: char = '\\';
 
+/// A preprocessor for expanding the `{{# playpen}}` and `{{# include}}` 
+/// helpers in a chapter.
 pub struct LinkPreprocessor;
 
 impl LinkPreprocessor {
+    /// Create a new `LinkPreprocessor`.
     pub fn new() -> Self {
         LinkPreprocessor
     }
diff --git a/src/preprocess/mod.rs b/src/preprocess/mod.rs
index 091604d6..6f82c338 100644
--- a/src/preprocess/mod.rs
+++ b/src/preprocess/mod.rs
@@ -1,3 +1,5 @@
+//! Book preprocessing.
+
 pub use self::links::LinkPreprocessor;
 
 mod links;
@@ -8,18 +10,29 @@ use errors::*;
 
 use std::path::PathBuf;
 
+/// Extra information for a `Preprocessor` to give them more context when 
+/// processing a book.
 pub struct PreprocessorContext {
+    /// The location of the book directory on disk.
     pub root: PathBuf,
+    /// The book configuration (`book.toml`).
     pub config: Config,
 }
 
 impl PreprocessorContext {
-    pub fn new(root: PathBuf, config: Config) -> Self {
+    /// Create a new `PreprocessorContext`.
+    pub(crate) fn new(root: PathBuf, config: Config) -> Self {
         PreprocessorContext { root, config }
     }
 }
 
+/// An operation which is run immediately after loading a book into memory and 
+/// before it gets rendered.
 pub trait Preprocessor {
+    /// Get the `Preprocessor`'s name.
     fn name(&self) -> &str;
+
+    /// Run this `Preprocessor`, allowing it to update the book before it is
+    /// given to a renderer.
     fn run(&self, ctx: &PreprocessorContext, book: &mut Book) -> Result<()>;
 }
\ No newline at end of file
diff --git a/src/renderer/html_handlebars/mod.rs b/src/renderer/html_handlebars/mod.rs
index f1df6d8d..aca09dbe 100644
--- a/src/renderer/html_handlebars/mod.rs
+++ b/src/renderer/html_handlebars/mod.rs
@@ -1,3 +1,5 @@
+#![allow(missing_docs)] // FIXME: Document this
+
 pub use self::hbs_renderer::HtmlHandlebars;
 
 mod hbs_renderer;
diff --git a/src/theme/mod.rs b/src/theme/mod.rs
index dc31a247..68bb4411 100644
--- a/src/theme/mod.rs
+++ b/src/theme/mod.rs
@@ -1,3 +1,4 @@
+#![allow(missing_docs)] // FIXME: Document this
 pub mod playpen_editor;
 
 use std::path::Path;
diff --git a/src/utils/mod.rs b/src/utils/mod.rs
index 255a7f77..56291aeb 100644
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -1,3 +1,5 @@
+#![allow(missing_docs)] // FIXME: Document this
+
 pub mod fs;
 mod string;
 use errors::Error;