"The Hidden Game of Baseball" is a book by John Thorn and Pete Palmer that explores advanced statistics in baseball. It introduces concepts like on-base percentage and slugging percentage, which provide deeper insights into player performance beyond traditional metrics like batting average. The authors argue that understanding these hidden aspects of the game can enhance appreciation for baseball strategy. They emphasize the importance of data analysis in evaluating players and teams, making the book a significant contribution to the field of sports analytics and a valuable resource for fans and analysts alike.