Leon Eisenberg, M.D., D.Sc. (August 8, 1922 – September 15, 2009) was an American child psychiatrist, social psychiatrist and medical educator who "transformed child psychiatry by advocating research into developmental problems" (David DeMaso). He was credited with a number of "firsts" in medicine and psychiatry - in child psychiatry, autism, and the controversies around autism, randomized clinical trials (RCTs), social medicine, global health, affirmative action, and evidence-based psychiatry. Having retired in 1967 from Johns Hopkins Hospital Department of Child and adolescent psychiatry (he was the chairman of the department after Leo Kanner) and from Harvard Medical School in 1988, he continued as The Maude and Lillian Presley Professor of Social Medicine and Psychiatry Emeritus (and actively serving - lecturing, researching and writing, and mentoring) in the Department of Global Health and Social Medicine of the Harvard Medical School in the Longwood Medical Area of Boston until a few months before his death in 2009. He received both his BA and MD degrees from the Perelman School of Medicine at the University of Pennsylvania, taught previously at both the University of Pennsylvania and Johns Hopkins University, and was Chief of Psychiatry at both Johns Hopkins Hospital in Baltimore and the Massachusetts General Hospital in Boston during formative periods in psychiatry for each institution.