more documentation
diff --git a/doc/Makefile b/doc/Makefile
index f19a957..397d629 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -14,6 +14,8 @@
 
 .PHONY: help clean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
 
+default: html
+
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
 	@echo "  html       to make standalone HTML files"