diff --git a/book/src/SUMMARY.md b/book/src/SUMMARY.md
index ece03a0..533c0e7 100644
--- a/book/src/SUMMARY.md
+++ b/book/src/SUMMARY.md
@@ -12,6 +12,7 @@
   * Core Only
   * Volatile Destination
 * Broad Concepts
+  * CPU
   * BIOS
   * Working RAM
   * IO Registers