diff --git a/episodes/introduction.md b/episodes/introduction.md
index 62a325a1..7065d231 100644
--- a/episodes/introduction.md
+++ b/episodes/introduction.md
@@ -81,6 +81,18 @@ accessibility purposes'}`
 
 ![You belong in The Carpentries!](https://raw.githubusercontent.com/carpentries/logo/master/Badge_Carpentries.svg){alt='Blue Carpentries hex person logo with no text.'}
 
+::::::::::::::::::::::::::::::::::::: callout
+
+Callout sections can highlight information.
+
+They are sometimes used to emphasise particularly important points
+but are also used in some lessons to present "asides": 
+content that is not central to the narrative of the lesson,
+e.g. by providing the answer to a commonly-asked question.
+
+::::::::::::::::::::::::::::::::::::::::::::::::
+
+
 ## Math
 
 One of our episodes contains $\LaTeX$ equations when describing how to create