diff --git a/book/src/plumbing.md b/book/src/plumbing.md
index b1223836..4de5dfde 100644
--- a/book/src/plumbing.md
+++ b/book/src/plumbing.md
@@ -256,7 +256,7 @@ enum HelloWorldGroupKey__ {
 The `Query` trait that we saw earlier includes a method `group_key` for wrapping
 the key for some individual query into the group key.
 
-### Group storege
+### Group storage
 
 The "group storage" is the actual struct that contains all the hashtables and
 so forth for each query. The types of these are ultimately defined by the