Playing Twenty-One as a Martial Art. There are many others. As a basic guide, when you look at any book on card counting, pick one that follows the same basic theories and methods espoused by Thorp in his presentation of his Point Count systems. Tens and Aces are counted with a minus value, and low cards are counted with a plus value. All bet raises should be made as a result of the cards remaining to be dealt being rich in Tens and Aces.
Small bets are placed when the count is negative, i.e., the cards remaining are rich in low cards.
Playing decisions are also made based on the count. Beware of books that have systems that are not following the above guidelines. Especially beware of any book that says you can beat blackjack without counting cards. All of your playing strategy and betting decisions should be made according to the count. As for how much you should bet, this is one of the most tricky and difficult questions to answer, for any expert.