diff --git a/book-example/book.toml b/book-example/book.toml
index e730b43e..1c2e9699 100644
--- a/book-example/book.toml
+++ b/book-example/book.toml
@@ -5,3 +5,6 @@ author = "Mathieu David"
 
 [output.html]
 mathjax-support = true
+
+[output.html.playpen]
+editable = true
diff --git a/book-example/src/SUMMARY.md b/book-example/src/SUMMARY.md
index dd703380..078eef90 100644
--- a/book-example/src/SUMMARY.md
+++ b/book-example/src/SUMMARY.md
@@ -13,6 +13,7 @@
     - [Theme](format/theme/theme.md)
         - [index.hbs](format/theme/index-hbs.md)
         - [Syntax highlighting](format/theme/syntax-highlighting.md)
+        - [Editor](format/theme/editor.md)
     - [MathJax Support](format/mathjax.md)
     - [Rust code specific features](format/rust.md)
 - [For Developers](lib/index.md)
diff --git a/book-example/src/format/theme/editor.md b/book-example/src/format/theme/editor.md
new file mode 100644
index 00000000..4af22e49
--- /dev/null
+++ b/book-example/src/format/theme/editor.md
@@ -0,0 +1,40 @@
+# Editor
+
+In addition to providing runnable code playpens, mdBook optionally allows them to be editable. In order to enable editable code blocks, the following needs to be added to the ***book.toml***:
+
+```toml
+[output.html.playpen]
+editable = true
+```
+
+To make a specific block available for editing, the attribute `editable` needs to be added to it:
+
+<pre><code class="language-markdown">```rust,editable
+fn main() {
+    let number = 5;
+    print!("{}", number);
+}
+```</code></pre>
+
+The above will result in this editable playpen:
+
+```rust,editable
+fn main() {
+    let number = 5;
+    print!("{}", number);
+}
+```
+
+Note the new `Undo Changes` button in the editable playpens.
+
+## Customizing the Editor
+
+By default, the editor is the [Ace](https://ace.c9.io/) editor, but, if desired, the functionality may be overriden by providing a different folder:
+
+```toml
+[output.html.playpen]
+editable = true
+editor = "/path/to/editor"
+```
+
+Note that for the editor changes to function correctly, the `book.js` inside of the `theme` folder will need to be overriden as it has some couplings with the default Ace editor.
diff --git a/book-example/src/misc/contributors.md b/book-example/src/misc/contributors.md
index f0184c15..94191db4 100644
--- a/book-example/src/misc/contributors.md
+++ b/book-example/src/misc/contributors.md
@@ -13,3 +13,4 @@ If you have contributed to mdBook and I forgot to add you, don't hesitate to add
 - Fu Gangqiang ([FuGangqiang](https://github.com/FuGangqiang))
 - [Michael-F-Bryan](https://github.com/Michael-F-Bryan)
 - [Chris Spiegel](https://github.com/cspiegel)
+- [projektir](https://github.com/projektir)