Steven N. Blair, PED, is a professor at the Arnold School of Public Health at the University of South Carolina in Columbia. His research focuses on the associations between lifestyle and health, with a specific emphasis on exercise, physical fitness, body composition, and chronic disease. As one of the most highly cited exercise scientists currently active in research, Dr. Blair has published more than 475 articles, chapters, and books in scientific and professional literature. He also was the senior scientific editor for the U.S. Surgeon General's Report on Physical Activity and Health.Blair is a fellow of the American College of Epidemiology, Society of Behavioral Medicine, American… College of Sports Medicine, American Heart Association, and American Academy of Kinesiology and Physical Education. He was also elected to membership in the American Epidemiological Society. He was the first president of the National Coalition for Promoting Physical Activity and is a past president of the American College of Sports Medicine and the American Academy of Kinesiology and Physical Education.Andrea L. Dunn, PhD, is a senior scientist at Klein Buendel, Inc., a health communication research company in Golden, Colorado. She served as the project director and co-investigator of Project Active, ACT (Activity Counseling Trial), and PRIME (Physically Ready for Invigorating Movement Every day), all large-scale clinical trials involving sedentary adults. These studies helped sedentary adults learn behavioral skills vital for adopting and maintaining an active lifestyle. She has conducted public health research on physical activity interventions to improve a variety of health outcomes but particularly to improve mental health.Dunn cowrote the curriculum forProject Activeand PRIMEthat is the basis for Active Living Every Day. She has led intervention groups that tested the approach, and she is the lead author of the Journal of the American Medical Association article describing its efficacy.Dunn has an MS in psychology and a PhD in exercise science and is a fellow of the American College of Sports Medicine and the Society of Behavioral Medicine.Bess H. Marcus, PhD, is Professor and Chair of the Department of Family and Preventive Medicine at the University of California, San Diego where she pursues research on physical activity and public health with funding from the National Institutes of Health. Dr. Marcus is a clinical health psychologist who has spent the past 25 years conducting research on physical activity behavior and has published more than 175 papers and book chapters as well as three books on this topic.Dr. Marcus has developed a series of assessment instruments to measure psychosocial mediators of physical activity behavior and has also developed low-cost interventions to promote physical activity behavior in community, workplace, and primary care settings. Dr. Marcus uses a variety of channels to promote physical activity including print, telephone, and the Internet. Dr. Marcus has participated in panels for the American Heart Association, American College of Sports Medicine, Centers for Disease Control and Prevention, and National Institutes of Health; these panels have created recommendations regarding the quantity and intensity of physical activity necessary for health benefits. Dr. Marcus also does work examining the benefits of exercise for women who want to stop smoking. Marcus was a contributing author to the Surgeon General’s Report on Physical Activity and Health and a member of the Executive Committee for the National Physical Activity Plan. Marcus served as an advisor on the curriculum development for the Cooper Institute’s Project Active study that created Active Living Every Day.Ruth Ann Carpenter, MS, RD,is the founder and lead integrator at Health Integration, LLC. She was the cocreator of the curriculum and group cofacilitator for The Cooper Institute’s Project Active study that created the Active