diff --git a/README.md b/README.md
index a8fa8af..154cacd 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,8 @@
 This library injects functions for string encryption and decryption into [exim4](https://www.exim.org/). It is basically
 glue code that exports certain parts of the [libsodium library](https://github.com/jedisct1/libsodium) to exim at runtime.
 
+[[_TOC_]]
+
 ## Installation
 
 These instructions are currently only tested on [Debian](https://www.debian.org) and
@@ -183,4 +185,4 @@ Output:
 
 Keys in arguments and environment variables are expected to be base64 encoded (as produced by the library).
 Keys in files need to be raw bytes with no encoding, ciphertext should always be base64-encoded.
-```
\ No newline at end of file
+```