Alchemy has traditionally been viewed as 'the history of an error', an example of medieval gullibility and greed, in which alchemists tried to turn lead into gold, create fabulous wealth and find the elixir of life. But alchemy has also been described as 'the mightiest secret that a man can possess', and it obsessed the likes of Isaac Newton, Robert Boyle, and many of the founders of modern science. This book explores the history of the so-called Royal Art, from its mysterious beginnings in Egypt and China, through the Hellenistic world and the early years of Islam and into mediaeval Europe. Some of the greatest minds of the Middle Ages, figures such as Albertus Magnus, Roger Bacon, and Thomas Aquinas were drawn to alchemy, and legendary alchemists such as Nicholas Flamel were thought to have actually succeeded in finding The Philosopher's Stone. During the Renaissance, Paracelsus and his followers helped revolutionize medicine, and during the seventeenth century, alchemy played a major role in paving the way for modern science. During the twentieth century, it became a focus of interest for the psychologist Carl Jung and his followers, who believed that the alchemists had discovered the unconscious. In this fully revised edition, Sean Martin has expanded the sections on Chinese and Indian alchemy and has added new material on the relationship between alchemy and early modern science, while also making a fresh assessment of this most enduringly mysterious and fascinating of subjects, to which all others have been described as 'child's play'.