MidAtlantic Book Publishers Association

On SPAN's website at http://www.spannet.org/article-walls-indexing.htm is an excellent article on how important a good index is to selling your nonfiction titles. I'm not going to give the whole thing here, but wanted to post a snippet that I think captures the flavor of the piece, and says what I find most important about a good index:

Indexes do sell books! But beware: all indexes are not the same. A good index contains all the important topics, subtopics and cross references grouped according to readers’ needs.