I've bought a dozen of the best-known card books and this is the "best of the best." It contains clear, concise descriptions of hundreds of card games.
Its author, Mr. Parlett, is considered one of today's highest authorities on cards. This book shows why. You can look up just about any card game, widely-played or obscure, and find rules sufficient to play the game. The explanations are simple and readable -- but also complete and authoritative.
For those who only play certain games, this is a great source for finding alternatives. Look up any game, and you'll find descriptions of related games to try. For those who get their card game rules from the web, it's really nice to own a single, comprehensive sourcebook you can carry anywhere and read without your laptop.
I highly recommend this book to any card player, from novice to advanced. It's well worth the money and something you'll use for years to come.