diff --git a/book-example/book.toml b/book-example/book.toml
index 0c5ece6b..d21c8487 100644
--- a/book-example/book.toml
+++ b/book-example/book.toml
@@ -3,6 +3,8 @@ title = "mdBook Documentation"
 description = "Create book from markdown files. Like Gitbook but implemented in Rust"
 authors = ["Mathieu David", "Michael-F-Bryan"]
 language = "en"
+
+[rust]
 edition = "2018"
 
 [output.html]
diff --git a/book-example/src/format/config.md b/book-example/src/format/config.md
index a76c9d08..82c896c3 100644
--- a/book-example/src/format/config.md
+++ b/book-example/src/format/config.md
@@ -59,9 +59,19 @@ language = "en"
 
 ### Rust options
 
-Options for the Rust compiler used for playpen.
+Options for the Rust language, relevant to running tests and playground
+integration.
 
-- **edition**: Rust edition to use by default for the code snippets. Defaults to `rustdoc` defaults (2015).
+- **edition**: Rust edition to use by default for the code snippets. Default
+  is "2015". Individual code blocks can be controlled with the `edition2015`
+  or `edition2018` annotations, such as:
+
+  ~~~text
+  ```rust,edition2015
+  // This only works in 2015.
+  let try = true;
+  ```
+  ~~~
 
 ### Build options
 
diff --git a/src/config.rs b/src/config.rs
index b0b09f90..36190ebf 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -72,7 +72,7 @@ pub struct Config {
     pub book: BookConfig,
     /// Information about the build environment.
     pub build: BuildConfig,
-    /// Information passed to the Rust playground
+    /// Information about Rust language support.
     pub rust: RustConfig,
     rest: Value,
 }
@@ -340,6 +340,7 @@ impl<'de> Deserialize<'de> for Config {
 impl Serialize for Config {
     fn serialize<S: Serializer>(&self, s: S) -> std::result::Result<S::Ok, S::Error> {
         use serde::ser::Error;
+        // TODO: This should probably be removed and use a derive instead.
 
         let mut table = self.rest.clone();
 
@@ -349,8 +350,10 @@ impl Serialize for Config {
                 return Err(S::Error::custom("Unable to serialize the BookConfig"));
             }
         };
+        let rust_config = Value::try_from(&self.rust).expect("should always be serializable");
 
         table.insert("book", book_config).expect("unreachable");
+        table.insert("rust", rust_config).expect("unreachable");
         table.serialize(s)
     }
 }
@@ -449,55 +452,17 @@ pub struct RustConfig {
     pub edition: Option<RustEdition>,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
 /// Rust edition to use for the code.
 pub enum RustEdition {
     /// The 2018 edition of Rust
+    #[serde(rename = "2018")]
     E2018,
     /// The 2015 edition of Rust
+    #[serde(rename = "2015")]
     E2015,
 }
 
-impl Serialize for RustEdition {
-    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        match self {
-            RustEdition::E2015 => serializer.serialize_str("2015"),
-            RustEdition::E2018 => serializer.serialize_str("2018"),
-        }
-    }
-}
-
-impl<'de> Deserialize<'de> for RustEdition {
-    fn deserialize<D>(de: D) -> std::result::Result<Self, D::Error>
-    where
-        D: Deserializer<'de>,
-    {
-        use serde::de::Error;
-
-        let raw = Value::deserialize(de)?;
-
-        let edition = match raw {
-            Value::String(s) => s,
-            _ => {
-                return Err(D::Error::custom("Rust edition should be a string"));
-            }
-        };
-
-        let edition = match edition.as_str() {
-            "2018" => RustEdition::E2018,
-            "2015" => RustEdition::E2015,
-            e => {
-                return Err(D::Error::custom(format!("Unknown Rust edition: {}", e)));
-            }
-        };
-
-        Ok(edition)
-    }
-}
-
 /// Configuration for the HTML renderer.
 #[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
diff --git a/src/renderer/html_handlebars/hbs_renderer.rs b/src/renderer/html_handlebars/hbs_renderer.rs
index 302ec419..14012c12 100644
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -808,7 +808,7 @@ mod tests {
     fn add_playpen_edition2015() {
         let inputs = [
           ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playpen\"><code class=\"language-rust edition2015\">\n<span class=\"boring\">#![allow(unused_variables)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
+           "<pre class=\"playpen\"><code class=\"language-rust edition2015\">\n<span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
           ("<code class=\"language-rust\">fn main() {}</code>",
            "<pre class=\"playpen\"><code class=\"language-rust edition2015\">fn main() {}\n</code></pre>"),
           ("<code class=\"language-rust edition2015\">fn main() {}</code>",
@@ -832,7 +832,7 @@ mod tests {
     fn add_playpen_edition2018() {
         let inputs = [
           ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playpen\"><code class=\"language-rust edition2018\">\n<span class=\"boring\">#![allow(unused_variables)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
+           "<pre class=\"playpen\"><code class=\"language-rust edition2018\">\n<span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
           ("<code class=\"language-rust\">fn main() {}</code>",
            "<pre class=\"playpen\"><code class=\"language-rust edition2018\">fn main() {}\n</code></pre>"),
           ("<code class=\"language-rust edition2015\">fn main() {}</code>",