diff --git a/complexity/README.md b/complexity/README.md
new file mode 100644
index 0000000..37ead3a
--- /dev/null
+++ b/complexity/README.md
@@ -0,0 +1,3 @@
+#Complexity
+
+* [The Complexity of Theorem-Proving Procedures](http://www.chell.co.uk/media/product/_master/1/files/cook_complexity_of_theorem_proving_procedures_19712.pdf) by Stephen Cook