diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index 5815f8c..a79e142 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -1319,6 +1319,11 @@
 \end{methoddesc}
 
 
+Files support the iterator protocol.  Each iteration returns the same
+result as \code{\var{file}.readline()}, and iteration ends when the
+\method{readline()} method returns an empty string.
+
+
 File objects also offer a number of other interesting attributes.
 These are not required for file-like objects, but should be
 implemented if they make sense for the particular object.