diff --git a/doc/functions.xml b/doc/functions.xml
index f790512e7db1..b2e450972947 100644
--- a/doc/functions.xml
+++ b/doc/functions.xml
@@ -294,6 +294,22 @@ merge:"diff3"
 
 </section>
 
+<section xml:id="sec-debug">
+  <title>Debugging Nix Expressions</title>
+
+  <para>Nix is a unityped, dynamic language, this means every value can
+  potentially appear anywhere. Since it is also non-strict, evaluation order
+  and what ultimately is evaluated might surprise you. Therefore it is important
+  to be able to debug nix expressions.</para>
+
+
+  <para>In the <literal>lib/debug.nix</literal> file you will find a number of
+  functions that help (pretty-)printing values while evaluation is runnnig. You
+  can even specify how deep these values should be printed recursively, and
+  transform them on the fly. Please consult the docstrings in
+  <literal>lib/debug.nix</literal> for usage information.</para>
+</section>
+
 
 <section xml:id="sec-fhs-environments">
   <title>buildFHSUserEnv</title>