diff --git a/book/intro/book.md b/book/intro/book.md
index a3523e5..0a10867 100644
--- a/book/intro/book.md
+++ b/book/intro/book.md
@@ -28,7 +28,7 @@ Text-based files are digital files on your computer that you can open in a text
 
 YAML (or YML) is a text-based file format that is primarily used to store data. It is useful because it is easy for humans to read and write, and easy for machines to _parse_ and generate., which is why YAML is often used for configuration files. Here is an example of a YAML file...can you tell what information is being stored?
 
-```
+```yaml
 parts:
   - caption: Your First TeachBook!
     chapters:
@@ -57,4 +57,4 @@ Have you ever used LaTeX? It turns out there are a lot of similarities with this
 4. Sometimes you can spend more time than you like troubleshooting "bugs" that turn out to be simple syntax errors.
 ``` 
 
-Let's see how these books are made!
\ No newline at end of file
+Let's see how these books are made!