diff --git a/lenses/lenses.scrbl b/lenses/lenses.scrbl
index 1de4bbb..c959674 100644
--- a/lenses/lenses.scrbl
+++ b/lenses/lenses.scrbl
@@ -4,15 +4,20 @@
           (for-label lenses
                      racket/base))
 
-@title{Lenses}
-
 @(define lenses-eval (make-base-eval))
 @(lenses-eval '(require "main.rkt"))
 @(define-syntax-rule (lenses-examples datum ...)
    (examples #:eval lenses-eval datum ...))
 
+@title{Lenses}
+
 @defmodule[lenses]
 
+This library includes functions and forms for working with @italic{lenses}.
+A lens is a pure function that operates on some small piece of a larger
+structure. Think of them as a more general representation of getters and
+setters in object-oriented languages.
+
 @author[@author+email["Jack Firth" "jackhfirth@gmail.com"]]
 
-source code: @url["https://github.com/jackfirth/lenses"]
\ No newline at end of file
+source code: @url["https://github.com/jackfirth/lenses"]