This book presents the first integrated treatment of the mechanical or corpuscular philosophy of Robert Boyle, one of the leading English natural philosophers of the Scientific Revolution. It examines the central concepts of his philosophy, including the theory of matter and its qualities, causation, the laws of nature, motion and the incorporeal. The book is divided into two parts - the first examining the the manner in which Boyle distinguished between various qualities, his view on the perception of these qualities and the ontological status of the sensible qualities. The second part examines Boyle's mechanism in general. Through detailed examination of Boyle's conceptions of motion, laws and space, it is argued that Boyle uphold's a unique view of the causal interaction of natural bodies. Boyle wrote as a natural philosopher and a committed experimentalist. This book is the first ever that is entirely given over to an exposition of that philosophy. It will therefore be of vital interest to any serious scholar of the history and philosophy of science.