Isaac "Jack" Starr (March 6, 1895 – June 22, 1989), known as the father of ballistocardiography, was an American physician, heart disease specialist, and clinical epidemiologist notable for developing the first practical ballistocardiograph. His early academic positions included being an assistant professor in pharmacology and later the first Hartzell Professor of Research Therapeutics at the Perelman School of Medicine at the University of Pennsylvania as well as dean of the school from 1945 to 1948.