This is not an attempt to popularize the life of the founder of modern chemistry, but a studious, authenticated study for the serious reader of scientific biography. Here is a picture of a man of insatiable curiosity, of solitary working habits, with health and eyes as obstacles to his achievements. Son of the famous Earl of Cork, Hoyle came from a background of position and wealth; he lived in Ireland and England, spent months as a dilettante on the Continent, but his years at Oxford steadied him into devoting himself to the science of chemistry. His sudden fame was an incentive for the Royal Society, and his influence on thought, stimulating and widespread, popularized science in expounding the new disciplines and philosophies. Typical of the 17th century, he embodied the theologian, scientist, humanist, Christian gentleman, and opened the way for Newton and others.