diff --git a/CHANGES.md b/CHANGES.md
index f312b69..8254505 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,6 +10,7 @@ v1.1.0 (Month DD, YYYY)
 - Added `pdfioContentPathEnd` function.
 - Added protection against opening multiple streams in the same file at the
   same time.
+- Documentation updates (Issue #37)
 - Fixed "install-shared" target (Issue #32)
 - Fixed `pdfioFileGet...` metadata APIs (Issue #33)
 - Fixed `pdfioContentMatrixRotate` function.
diff --git a/pdfio-stream.c b/pdfio-stream.c
index 5fd54cc..45a21b0 100644
--- a/pdfio-stream.c
+++ b/pdfio-stream.c
@@ -1,7 +1,7 @@
 //
 // PDF stream functions for PDFio.
 //
-// Copyright © 2021-2022 by Michael R Sweet.
+// Copyright © 2021-2023 by Michael R Sweet.
 //
 // Licensed under Apache License v2.0.  See the file "LICENSE" for more
 // information.
@@ -366,6 +366,13 @@ pdfioStreamConsume(pdfio_stream_t *st,	// I - Stream
 //
 // 'pdfioStreamGetToken()' - Read a single PDF token from a stream.
 //
+// This function reads a single PDF token from a stream.  Operator tokens,
+// boolean values, and numbers are returned as-is in the provided string buffer.
+// String values start with the opening parenthesis ('(') but have all escaping
+// resolved and the terminating parenthesis removed.  Hexadecimal string values
+// start with the opening angle bracket ('<') and have all whitespace and the
+// terminating angle bracket removed.
+//
 
 bool					// O - `true` on success, `false` on EOF
 pdfioStreamGetToken(