Perelman Department of Dermatology at the NYU Langone Medical Center in New York City, with additional teaching appointments at Southhampton Hospital and the New York College of Osteopathic Medicine. Dr Hennessey graduated from Michigan State University College of Human Medicine in 1975, and completed a residency in Internal Medicine at New England Deaconess Hospital in Boston. He then did a residency in Dermatology, followed by a Malignant Melanoma Fellowship at New York University Medical Center. Dr Hennessey has continued his interest in cutaneous malignancies and HIV-related skin diseases in his clinical practice in New York City and the Hamptons for over 30 years.