Born 1574 in Kent, died 1657 aged 83 years.
Harvey, went to Cambridge and graduated in 1597 aged 23 years. He then went to the university of Padua in Italy to study under Hieronymus Fabricus, graduating in 1602. Fabricus was working on the function of the valves in veins.
Harvey's main claim to fame is that he put the concept of the circulatory system together. He did this by working it out methodically and by observation. The older fashioned way of coming to a conclusion about something was by intuition and thinking. Prior to Harvey's work, the understanding of the circulation was based upon the work of Galen (a great dissector) which in turn had advanced upon the ideas of Aristotle; at Harveys time it was felt that blood was made in the liver from digested food and was then sent to the rest of the body to feed it where the blood disappeared, tiny channels in the intra ventricular septum were supposed to let the blood pass from the right side of the heart to the left.
Harvey examined veins and noted that the valves in them permitted flow of the blood only back towards the heart. In one of his experiments he looked at the veins in the arm and noted that he could empty them by stroking towards the heart. If he also stopped flow in the vein by pressing his finger on the vein and stroked it, he noted that the flow in the vein only went up the arm towards the heart.
His examination of the heart lead him to conclude the the arteries carried blood away from the heart. He did not have any way of discovering what joined the arteries to the veins but he postulated that there must be some such connection. Many other doctors did not agree with Harvey and Harveys notion was considered controversial for a long time. It was not until the discovery of the microscope that capillaries were seen by Malphigni and thus the circuit of the circulation was completed. Harvey, was unfortunately dead at this time.