diff --git a/README.md b/README.md
index 5651737..1c32cd8 100644
--- a/README.md
+++ b/README.md
@@ -3,4 +3,10 @@
 A lecture from ASPP 2024.
 
 
+## Extra resources
+
+ * Online textbook on operating systems, processes, threads, etc.
+    * [Operating Systems: Three Easy Pieces](https://pages.cs.wisc.edu/~remzi/OSTEP/#book-chapters)
+    * Chapters 4, 13, and 26 are particularly relevant.
+    * But the whole book is interesting.