Usually a number like 336.d6 means it is in the nonfiction section of the library. SF might indicate the author or the section of nonfiction it is in. When I went to Worldcat I couldn't even find any libraries that had this book but I had just gotten home from work and I was tired so maybe I didn't do it right. -- Jamie in Michigan Currently Reading: The Great Arizona Orphan Abduction by Linda Gordon Earn cash for answering trivia questions every 3 hours: http://instantcashsweepstakes.com/invitations/ref_link/49497 See everything I've read this year at: www.michiganrxtech.com/books.html