Once studied by economists primarily to analyze antitrust implications of leagues or labor contracts with players, the sports world has now been identified by pathbreaking economists as a model of universal economic behavior. These economists have coined the term sportometrics to describe their two-way vision of sports as a reflection of the economic world and as a model for further study of economic behavior and principles. The essays are thus not merely the economics of sport--the profits and losses of various players, managers, owners, and spectators--but also explorations into the economic and mathematical relationships between athletes' success and their earnings, between the structure of high school athletic competition and the players' later careers in professional sports, and between the length of player contracts and the number of players on the disabled list, to name a few. The authors see in these relationships the individual and institutional behavior of athletes, managers, coaches, and sports associations and connect them to the broader arena of labor markets, commodity cartels, crime, income distribution, individual productivity, and other areas. Contracts, rules, and ability are constraints to the economic players, and their economic behavior is analyzed in terms of choices made within constraints. With these essays, economists and industry specialists will be able to better understand both the dynamics of sports as an industry and the economic behavior of institutions and individuals in general.