An ancient doctor who advocated the therapeutic benefits of wine and passive exercise was bound to be popular. But Asclepiades of Bithynia did far more than reform much of traditional Hippocratic therapeutic practice; he devised an extraordinary physical theory which he used to explain all biological phenomena in uniformly simple terms. His work laid the theoretical basis for the antitheoretical medical sect called Methodism. Though none of this work survives, Asclepiades was the subject of numerous ancient testimonia, from which this book attempts to reconstruct many details of his theory. His ideas offer a fascinating glimpse into the ways in which Hellenistic philosophy and medicine interacted, and provide an introduction to one of the most intriguing doctrinal disputes in Greek science.