The new edition of this extraordinary book tells of the creation of the world champion checkers computer program, Chinook. In only two years, Chinook had become a worthy opponent to the world champion, and within four years had defeated all the world's top human players. Jonathan Schaeffer, the originator and leader of the Chinook team, provides an engrossing account of failures and successes. He describes the human story behind the program and his own feelings in learning from mistakes and technical problems in a continuous effort to improve Chinook's performance. Beginning in 1988, we follow the development of Chinook from an innocent question asked over lunch through to the final match against then world champion, Marion Tinsley, and ultimately to its recent triumph, perfecting checkers. As the story unfolds, readers are introduced to its key figures, and to the rules of checkers and the basics of computer game programs. As a result, all those interested in computing and games will enjoy this book.