A graduate of Yale College and the McGill University Faculty of Medicine in Montreal, Leffell completed his residency training in internal medicine at Cornell Cooperating Hospitals and then in dermatology at Yale-New Haven Hospital. He completed an NIH post-doctoral research fellowship in dermatology at Yale followed by a clinical fellowship in dermatologic surgery at the University of Michigan Medical School in Ann Arbor. Author of the popular book "Total Skin," Leffell is an expert clinician, specializing in skin cancer and melanoma diagnosis and surgical treatment using the Mohs micrographic technique. The Cutaneous Oncology Unit that he founded in 1988 now performs specialized surgical treatment on more than 3,500 patients annually. His major clinical interest is the management of skin cancer, including basal cell cancer, squamous cell cancer and melanoma. In 1996 Leffell was a member of the research group that discovered the skin cancer gene known as PTCH. In addition, he has conducted collaborative research clarifying the role of ultraviolet radiation in skin cancer and skin aging. Author of more than 200 publications, Leffell has also done research on epidemiologic aspects of skin cancer and wound healing. Dr. Leffell was the first CEO of the Yale Medical Group (now Yale Medicine) and served as Deputy Dean for Clinical Affairs at Yale for almost a decade.