John S Santelli Editor

Ralph J. DiClemente, PhD, is Charles Howard Candler Professor of Public Health and Pediatrics, Division of Infectious Diseases, Epidemiology, and Immunology, and associate director, Emory Center for AIDS Research.

John S. Santelli, MD, MPH, is the Harriet and Robert H. Heilbrunn Professor and chair of the Heilbrunn Department of Population and Family Health at Columbia University's Mailman School of Public Health, New York.

Richard A. Crosby, PhD, is DDI Endowed Professor and chair, Department of Health Behavior, University of Kentucky, College of Public Health, Lexington, Kentucky.