diff --git a/book/source/02-highlevel.md b/book/source/02-highlevel.md
index 9b5d5e8..75858c9 100644
--- a/book/source/02-highlevel.md
+++ b/book/source/02-highlevel.md
@@ -35,7 +35,7 @@ The GnuPG program binary is called `gpg`, thus the names "GnuPG" and "gpg" are o
 
 Note: The terms "pgp key" and "gpg key" are sometimes used. Since PGP and GnuPG are just two of many existing OpenPGP implementations, the proper term is "OpenPGP key" (or "OpenPGP certificate", more on that [later](certificates_chapter)).
 
-## The present
+## The OpenPGP version 4 era
 
 ### OpenPGP version 4