Part 1 Exercise adherence and public health: chronic disease - the dose response controversy, Steve Blair et al; exercise and mental health in clinical and free-living populations, Egil Martinsen and Tom Stephens; international physical activity patterns - a methodological perspective, Carl Caspersen, Tom Stephens and Rob Merritt. Part 2 Theory and determinants of physical activity: social-cognitive models, Gaston Godin; schema theory - an information processing focus, Deborah Kenzierski; the transtheoretical model - applications to exercise, James Prochaska and Bess Marcus. Part 3 Interventions for adoption and maintenance: clinical and community interventions to promote and support physical activity participation, Abby King; health care provider counselling to promote physical activity, Nola Pender et al; technological supports for sustaining exercise, Guy Dirkin; social marketing and population interventions, Rob Donovan and Neville Owen. Part 4 Special applications: the natural history of physical activity - a social cognitive model, Wendell Taylor et al; determinants of exercise in persons aged 65 years and older, Roy Shephard; physical activity and diet in weight loss, Denise Wilfly and Kelly Brownell.