diff --git a/man/man1/0intro.1 b/man/man1/0intro.1
index 6e86bb4..bbe7012 100644
--- a/man/man1/0intro.1
+++ b/man/man1/0intro.1
@@ -294,6 +294,53 @@
 .PP
 .HR ../man9 "Section (9p)
 describes the Plan 9 file protocol 9P.
+.PP
+These pages describe parts of the system
+that are new or different from Plan 9 from Bell Labs:
+.IP
+.IR 9 (1),
+.IR 9c (1),
+.IR 9p (1),
+.IR 9term (1),
+.I acidtypes
+in
+.IR acid (1),
+.IR cvs (1),
+.IR dial (1),
+.IR label (1),
+the
+.B MKSHELL
+variable in
+.IR mk (1),
+.IR namespace (1),
+.IR page (1),
+.IR psfonts (1),
+.IR rio (1),
+.IR web (1),
+.IR wintext (1)
+.IP
+.IR intro (3),
+.IR 9pclient (3),
+the
+.B unix
+network in
+.IR dial (3),
+.IR exits (3),
+.IR get9root (3),
+.IR getns (3),
+.IR notify (3),
+.IR post9pservice (3),
+.IR rfork (3),
+.IR sendfd (3),
+.IR udpread (3),
+.IR wait (3),
+.IR wctl (3)
+.IP
+.IR intro (4),
+.IR 9pserve (4),
+.IR import (4)
+.IP
+.IR openfd (9p)
 .SH DIAGNOSTICS
 In Plan 9, a program's exit status is an arbitrary text string,
 while on Unix it is an integer.