diff --git a/en_US.ISO8859-1/books/Makefile b/en_US.ISO8859-1/books/Makefile
index 9463b26c10..ecf27143de 100644
--- a/en_US.ISO8859-1/books/Makefile
+++ b/en_US.ISO8859-1/books/Makefile
@@ -1,16 +1,17 @@
 # $FreeBSD$
 
 SUBDIR = arch-handbook
 SUBDIR+= corp-net-guide
 SUBDIR+= design-44bsd
+SUBDIR+= dev-model
 SUBDIR+= developers-handbook
 SUBDIR+= faq
 SUBDIR+= fdp-primer
 SUBDIR+= handbook
 SUBDIR+= pmake
 SUBDIR+= porters-handbook
 
 ROOT_SYMLINKS= faq handbook
 
 DOC_PREFIX?= ${.CURDIR}/../..
 .include "${DOC_PREFIX}/share/mk/doc.project.mk"