Caplan 100Louis R. Caplan (born December 31, 1936) is an American physician who is a senior member of the Division of Cerebrovascular Disease at Beth Israel Deaconess Medical Center, Boston. He is a Professor of Neurology at Harvard Medical School, Boston, and the founder of the Harvard Stroke Registry at Beth Israel Deaconess Medical Center. Caplan is the author or editor of 37 books and more than 600 articles in medical journals.

Caplan is a senior member of the Division of Cerebrovascular Disease at Beth Israel Deaconess Medical Center, Boston. He is a member of many professional societies, serving as an officer on committees for the American Heart Association, the American Academy of Neurology, and the American Neurological Association. He has served as the Chair of both the Boston Society of Neurology and the Chicago Neurological Society.