This book traces the genesis, principles and practice of homeopathy, and discusses the reasons for its enduring popularity. Two hundred years ago, medicine had little to offer except blood letting and the administration of violent purgatives – practices which shortened the course of illness by hastening the death of the patient. Largely in reaction to what he correctly saw as the brutality and ineffectiveness of the medicine of his day, the eighteenth century German physician Samuel Hahnemann developed a system of therapeutics that he termed homeopathy. Ironically, while modern medicine has changed beyond recognition, homeopathy, with its roots in alchemy and metaphysics, continues to be practiced precisely as it was in Hahnemann's day. Readers of this book will enjoy the story of homeopathy and its almost magical attraction, whilst learning much from the authors' rational and scientific discussion of the biological, chemical and psychological questions that this treatment raises.