diff --git a/nostarch/book.toml b/nostarch/book.toml
index 169a02be0f..50d3dc0775 100644
--- a/nostarch/book.toml
+++ b/nostarch/book.toml
@@ -19,5 +19,8 @@ output-mode = "simple"
 [preprocessor.trpl-figure]
 output-mode = "simple"
 
+[preprocessor.trpl-heading]
+output-mode = "simple"
+
 [rust]
 edition = "2021"