diff --git a/README.md b/README.md
index eca58bc..45c7d63 100644
--- a/README.md
+++ b/README.md
@@ -167,6 +167,7 @@ A curated list of awesome mathematics resources.
 * [Mathematical Reasoning: Writing and Proof](https://www.tedsundstrom.com/mathreasoning) - Ted Sundstrom
 * [Logic and Proof](http://leanprover.github.io/logic_and_proof/) -  Jeremy Avigad, Robert Y. Lewis, and Floris van Doorn
 * [QED - an interactive textbook](https://teorth.github.io/QED) - Terence Tao
+* [Open Logic Textbook](http://builds.openlogicproject.org/) - collaborative effort, main contributors listed [here](https://openlogicproject.org/people/)
 
 ### Category Theory