This book examines the search for 'occult' or hidden forces in the two centuries after Newton's theory of gravity. It investigates how history has simplified the work of some of the key figures of the age, presenting them as 'legitimate' and removing their more complex motivations. This book is a scholarly but readable exploration of forces we rely upon (electricity) and ones we have abandoned (vital fluid, animal magnetism). Ranging across literature, drama, philosophy and science, it demonstrates how hopes, fears and anxieties around occult phenomena have been expressed over time.