Apologies for resurrecting an old thread, but I think I can help with this question.
The vast majority of older flatware found in the U.S. is of English or American origin. With that thought in mind, I'd recommend:
Encyclopedia of American Silver Manufacturers by Dorothy T. Rainwater (to save a few bucks, an older edition would be OK)
ANY of the books on British Hallmarks (Bradbury's is well known, but there should be plenty of cheaper options -- oh, and you don't need a big book, a simple pocket guide should do the trick)
A great way to search for used books online is to use
BookFinder.com -- it searches multiple sites for you. Also, every public library should have one or more books on British hallmarks, and they may have Rainwater as well. Finally, a lot of info on markings can be found online these days, here's one useful website:
www.silvercollection.it/hallmarks.html
If you are searching for a lot of markings on plated ware, you may need another reference or two -- and American coin silver (pre-sterling, before 1860-ish) can be complicated as there were MANY independent craftsmen with their own markings. But this should get you a start.
Good luck!
