diff --git a/.gitmodules b/.gitmodules
index 208f06a..fc993b6 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -13,9 +13,6 @@
 [submodule "book/external/Useful_python_code"]
 	path = book/external/Useful_python_code
 	url = https://github.com/TeachBooks/Useful_python_code.git
-[submodule "book/external/TeachBooks"]
-	path = book/external/TeachBooks
-	url = https://github.com/TeachBooks/TeachBooks.git
 [submodule "book/external/Sphinx-Image-Inverter"]
 	path = book/external/Sphinx-Image-Inverter
 	url = https://github.com/TeachBooks/Sphinx-Image-Inverter.git
diff --git a/book/external/TeachBooks b/book/external/TeachBooks
deleted file mode 160000
index eb5f90c..0000000
--- a/book/external/TeachBooks
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit eb5f90c86e6f9dd368c513b2d958f77fb941cae0