diff --git a/docs/LEARNING.md b/docs/LEARNING.md
index 53144aa1..a2f027da 100644
--- a/docs/LEARNING.md
+++ b/docs/LEARNING.md
@@ -29,6 +29,6 @@ These resources cover [Unity][] and [CppUTest][]; this track uses Unity.
 [CS50x]: https://www.edx.org/course/cs50s-introduction-to-computer-science
 [CodeChef]: https://www.codechef.com/ide
 [test-frameworks]: https://www.drdobbs.com/testing/unit-testing-in-c-tools-and-conventions/240156344
-[tdd]: https://pragprog.com/book/jgade/test-driven-development-for-embedded-c
+[tdd]: https://pragprog.com/titles/jgade/test-driven-development-for-embedded-c
 [Unity]: https://www.throwtheswitch.org/unity/
 [CppUTest]: https://cpputest.github.io/