The TOGA (Tropical Ocean and Global Atmosphere) Program was designed to study short-term climate variations. A 10-year international program, TOGA made El Nino a household word. This book chronicles the cooperative efforts of oceanographers and meteorologists, several U.S. government agencies, many other nations, and international scientific organizations to study El Nino and the Southern Oscillation (ENSO). It describes the progression from being unable to detect the development of large climate variations to being able to make and use rudimentary climate predictions, especially for some tropical countries. It examines the development of the TOGA Program, evaluates its accomplishments, describes U.S. participation in the program, and makes general recommendations for developing better understanding and predictions of climate variations on seasonal to interannual time scales.