Robert Boyle ranks with Newton and Einstein as one of the world's most important scientists. Aristocrat and natural philosopher, he was a remarkably wide-ranging and penetrating thinker - pioneering the modern experimental method, championing a novel mechanical view of nature, and reflecting deeply on philosophical and theological issues related to science. But, as Michael Hunter shows, Boyle was also a complex and contradictory personality, fascinated by alchemy and magic and privately plagued with doubts about faith and conscience, which troubled the rational vision he heralded. This extraordinary work is the first biography of Boyle in a generation, and the culminating achievement of a world-renowned expert on the scientist. Deftly navigating Boyle's voluminous published works as well as his personal letters and papers, Hunter's complete and intimate account gives us the man rather than the myth, the troubled introvert as well as the public campaigner. Lively, perceptive, and full of original insights, this is the definitive account of a remarkable man and the changing world in which he lived.