This book presents a new interpretation of how and why the discovery of the circulation of the blood in animals was made. It has long been known that the English physician William Harvey (1578–1657) was a follower of Aristotle, but his most strikingly ‘modern’ and original discovery – of the circulation of the blood – resulted from Harvey following Aristotle’s ancient programme of investigation into animals. This is a new reading of the most important discovery ever made in anatomy by one man and produces not only a radical re-reading of Harvey as anatomist, but also of Aristotle and his investigations of animals.

"I DESIRE this evening to give you some account of the life and labours of a very noble Englishman—William Harvey. William Harvey was born in the year 1578; and as he lived until the year 1657; he very nearly attained the age of 80. He was the son of a small landowner in Kent; who was sufficiently wealthy to send this; his eldest son; to the University of Cambridge; while he embarked the others in mercantile pursuits; in which they all; as time passed on; attained riches." -an excerpt

During his medical career, Harvey focused much of his research on the mechanics of blood flow in the human body. Most physicians of the 17th-century considered lungs responsible for moving the blood throughout the body. Harvey's famous "Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus" commonly was published in Latin at Frankfurt in 1628. At that time, Harvey was 50 years old. The first English translation appeared two decades later. Observing the functioning of the heart in living animals, he was able to see that systole was the active phase of the heart's movement, pumping out the blood by its muscular contraction. Then he saw that the valves in the veins permit the blood to flow only in the direction of the heart and to prove that the blood circulated around the body and returned to the heart.