diff --git a/src/main/scala/scalatutorial/sections/HigherOrderFunctions.scala b/src/main/scala/scalatutorial/sections/HigherOrderFunctions.scala
index 93f7ce62..74a08a9a 100644
--- a/src/main/scala/scalatutorial/sections/HigherOrderFunctions.scala
+++ b/src/main/scala/scalatutorial/sections/HigherOrderFunctions.scala
@@ -80,6 +80,12 @@ object HigherOrderFunctions extends ScalaTutorialSection {
    *
    * So, `Int => Int` is the type of functions that map integers to integers.
    *
+   * Similarly, `(A1, A2) => B` is the type of functions that take two arguments
+   * (of types `A1` and `A2`, respectively) and return a result of type `B`.
+   *
+   * More generally, `(A1, ..., An) => B` is the type of functions that take `n`
+   * arguments (of types `A1` to An`) and return a result of type `B`.
+   *
    * = Anonymous Functions =
    *
    * Passing functions as parameters leads to the creation of many small functions.