Duchenne de Boulogne was a French pioneer in neurology and one of the greatest clinicians of his day. His pathbreaking studies in electrotherapy and electrodiagnostics laid the foundations of muscular electrophysiology. Described many pathological conditions and authored important treatises on the psychophysiology of emotions and motor physiology. Invented an instrument to sample tissues inside the body - pioneering the procedure now known as biopsy - and a sophisticated electrotherapy apparatus.