As a supplement to other classroom materials and field experiences, Understanding the Game of the Environment should provide stimuli for discussion and review of ecological principles and their relevance to our daily existence. The illustrations, purposefully detailed and complex, are intended to provide a basis for in-depth discussion. We believe this bulletin also should be of value to special interest and youth organizations —members of the Youth Conservation Corps, Scouts, and others interested in understanding their environment. Understanding the Game of the Environment is a summary of major ecological principles and concepts viewed as a game in which living organisms interact with each other and their nonliving environment. The use of game terminology helps place a bewildering array of facts and relationships into an understandable framework. All students are familiar with games, and they recognize the necessity of defining the Playing Field, identifying the Players, and understanding the Rules of the Game. Similarly, students understand that when Rules are violated and Fouls are committed, the Players will be Penalized.