NIDDM is a common diseaese that exacts a considerable cost in terms of human suffering, morbidity and mortality. Since most of the morbidity and mortality of NIDDM arises from its long-term complications, prevention and early detect-ion have a tremendous human, social and economic impact. This study will eval-uate the effectiveness of behavior modification and pharmacologic interventions in preventing the development of NIDDM in subjects at high risk for the disease.