Do you want the identification for reselling or for your own knowledge?
Not that it makes a difference, but, if reselling and you can't find
the ISBN, it helps to compare . I sell at iOffer and use several tools
for pricing.
Alibris.com
Addall.com
are two sites that have good information. You could also check at
community boards for book lovers. Many on those boards have a wealth of
knowledge and are willing to share.
http://ioffer.com/users/funnyface2