diff --git a/books/free-programming-books-subjects.md b/books/free-programming-books-subjects.md
index 13099df7d..2ae099963 100644
--- a/books/free-programming-books-subjects.md
+++ b/books/free-programming-books-subjects.md
@@ -864,6 +864,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Programming Differential Privacy](https://programming-dp.com) - Joseph Near, Chiké Abuah (HTML, PDF)
 * [Security Engineering](https://www.cl.cam.ac.uk/~rja14/book.html)
 * [The Joy of Cryptography (2021)](https://joyofcryptography.com/pdf/book.pdf) - Mike Rosulek (PDF)
+* [The MoonMath Manual to zk-SNARKs](https://leastauthority.com/community-matters/moonmath-manual/) - Least Authority
 
 
 ### Software Architecture