The Complete IDIOT'S Guide to Options and Futures. by Scott Barrie Don't be fooled by the title of this book. Even you won't learn how to trade through its pages you'll have some basic ideas on futures after you finished it . Its a good starter. The exchanges web sites are good places also to get a lot of info. www.CBOT.com , www.CME.com. After the basics you can search for more advanced trading books. Check out this link : http://www.elitetrader.com/vb/showthread.php?s=&threadid=21123&perpage=6&pagenumber=2 However if you have not previous trading experience , my recommendation is to " Trade Yourself " first inside out. After you've understand how to trade Yourself ( psychologically) you'll be in good shape to start in the trading business. In other words, get to know your personality, your habits, your reaction to fear, your performance under pressure and your vision of a human being with a empty wallet. if you can master that ( the trading of yourself) you'll be in the right path to success. BTW I'm still trying harder and harder. The very best for you.
Check out the 50 page pdf from the NFA (National Futures Assoc.). http://www.nfa.futures.org/investor/uor.asp
if you're just starting out, I would highly recommend you join www.tradersbrain.com. Because beginner books are not ones you will want to read over and over. It's been a while for me. I think Jack Schwager is a good writer and he has a few called the "Complete something about futures" or something. Keep reading until you understand everything. Might not get it all in one book.