Since you were not specific about what you are interested in, I can only recommend general reference books-
A Guide Book of United States coins 2009 Red Book 62nd Ed.(obviously)
Official ANA Grading Standards 6th Ed./ANA
The Expert's Guide to Collecting & Investing In Rare Coins/Bowers (covers many different topics and quite educational)
Coin Collector's Survival Manual 6th Ed./Travers (have not read but I have heard good things about it)
Official Red Guide Book of United States Paper Money 2nd Ed./Friedberg
Brent Krueger is a good site, you might also want to check out Wizard Coin Supply
A Guide Book of United States coins 2009 Red Book 62nd Ed.(obviously)
Official ANA Grading Standards 6th Ed./ANA
The Expert's Guide to Collecting & Investing In Rare Coins/Bowers (covers many different topics and quite educational)
Coin Collector's Survival Manual 6th Ed./Travers (have not read but I have heard good things about it)
Official Red Guide Book of United States Paper Money 2nd Ed./Friedberg
Brent Krueger is a good site, you might also want to check out Wizard Coin Supply


















