Etienne Jules Marey was born in 1830, in Beaune, France. His interest was engineering but his father persuaded him to enter medical school. He studied in Paris and in 1859 completed his medical thesis on blood circulation under normal and pathological conditions, inaugurating a new era in cardiovascular hemodynamics. Moreover, he invented a practical sphygmograph, by modifying the instrument devised by the German professor of physiology Karl von Vierordt (1818-1884) and made it possible to provide accurate recordings of the arterial pulse. His basic instrument, with modifications, is still used today. Collaborating with JeanBaptiste-Auguste Chauveau (1827-1917), professor of veterinary physiology in Lyon, Marey developed a method to measure the rapidly changing intracardiac pressures and the apex beat simultaneously. Their novel double-lumen technique is considered as the real beginning of intracardiac pressure recordings. In further experiments, the two investigators were the first to describe and interpret simultaneous pressures in the right atrium and right ventricle, left ventricle and aorta and the pulmonary artery pressure. They also studied the atrial influence on the ventricular pressure curve, the isometric phase of ventricular contraction and the synchrony of left and right ventricular contraction. In 1867, Marey was appointed assistant professor at the Collège de France and in 1872 he was admitted to the Académie de Médecine. Except his novel work in cardiovascular physiology, Marey invented in 1881 the first chronophotographe camera establishing also modern cinematography.