"ACSM's Guidelines for Exercise Testing and Prescription" began as a concise summary of recommendations for exercise testing and prescription primarily for cardiac patients; it has now become one of the single most internationally read and referenced texts of its kind. This reference is a virtual pharmacopoeia of exercise guidelines in a broad spectrum of patients. In this new edition there is heightened emphasis on preventing illness in apparently healthy persons and those 'at risk', as well as treating patients with chronic disease. There are also two new chapters on methods for changing exercise behavior and legal issues.