Mark E. Josephson (1943-2017) was an American cardiologist and writer, who was in the 1970s one of the American pioneers of the medical cardiology subspecialty of cardiac electrophysiology. His book titled Clinical Cardiac Electrophysiology: Techniques and Interpretations is widely acknowledged as the definitive treatment of the discipline. He served as Herman Dana Professor of Medicine at Harvard Medical School, director of the Harvard-Thorndike Electrophysiology Institute and Arrhythmia Service and the chief of cardiology at Harvard University's Beth Israel Deaconess Medical Center in Boston.