Dr. Timothy Johnson (MD, MPH) is well-known as the medical editor for ABC News. He has reported on health care issues for Good Morning America since 1975. He also provides on-air analysis of medical news for World News Tonight, Nightline, and 20/20. Johnson holds joint positions in medicine at Harvard University and Massachusetts General Hospital in Boston. He is the founding editor of The Harvard Medical School Health Letter and coeditor of The Harvard Medical School Health Letter Book. He is the author of Dr. Timothy Johnson's OnCall Guide to Men's Health and coauthor with former U.S. Surgeon General Dr. C. Everett Koop of Let's Talk. Having completed seminary before medical school, Johnson also serves as assisting minister of the Community Covenant Church in West Peabody, Massachusetts.