The book presents 18 games and develops the concepts of game analysis and winning strategies. Students are encouraged to play these mathematical games together, collect data developed through their play, and analyze the data to develop a winning strategy. The book provides the basis for a six- to eight-week unit on mathematical games. Each chapter also functions as a self-contained and independent exploration so that selected chapters may be used as supplementary classroom investigations or as independent projects. The book includes both familiar games (such as Quadrangles and Nim) and many others that will be new and exciting to most readers. Through the exploration of mathematical games, 'The Play's the Thing' introduces teachers and students to the fun of play and to the mathematics behind the fun.