The following is an auction for an excellent book on modern forgeries of ancient coins made in Bulgaria. I bought a copy when it first came out and while all modern counterfeits are not there - there certainly are enough examples so that you can spot suspicious "looking" coins.
I don't know the seller in this case, so I am making no specific endorsement, you be the judge of the seller. But every collector of ancient coins should own this one.
http://cgi.ebay.com/ws/eBayISAPI.dl...m=8419566022Here is another good one - for sale by the author - perhaps he will autograph it if you win:
http://cgi.ebay.com/BOOK-On-Fakes-R...05_W0QQitemZ250000002299If you go to that auction you click the "ME" icon and you will find a lot of links to forgery discussion groups - Alan is the moderator.
The only better book on modern copies of ancients is Larson's book:
http://cgi.ebay.com/Book-10-Replica...mZ3945223424This last book is great because of the technical discussions of how counterfeiters produce their coins. I also understand that Charles Larson actually interviewed the infamous Mark Hoffman in prison regarding forgery. Hoffman is the Mormon document forger who got life in prison for two bombing murders in the Salt Lake area. He started his career in forgery making 1914 D Lincoln pennies - many of which he claims were certified. He also made Utah Territorial Gold coins and other numismatic rarities many of which remain UNDETECTED.