The book presents new results of computer-chess research in the areas of selective forward pruning, the efficient application of game-theoretical knowledge, and the behaviour of the search at increasing depths. It shows how to make sophisticated game-tree searchers more scalable at ever higher depths. Throughout the whole book, the high-speed and master-strength chess program "DarkThought" serves as a realistic test vehicle to conduct numerous experiments at unprecedented search depths. The extensive experimental evaluations provide convincing empirical evidence for the practical usefulness of the presented techniques. Advantages: - presentation of advanced and brand-new research results in computer chess (e.g. selective pruning and other search enhancements, improved endgame databases, etc.) - numerous experiments at unprecedented search depths - extensive experimental evaluation - practical usefulness of new techniques proven within strong state-of-the-art chess program "DarkThought" - includes detailed implementation skeletons in ANSI-C - contains concise introductions into the game of chess and the basics of computer chess in general