This book explores the practice, content, and transformations of chemistry in the period 1660-1730 by examining the life and work of Wilhelm Homberg (1653-1715) and status of chymistry at the Académie Royale des Sciences. The book is a triple biography—of a celebrated chymist, an institution, and a discipline. Born in Java, Homberg was formed intellectually through years of learned travel and trading secrets throughout Europe, and rose to become the Académie’s chief chymist and a favored person in the court of Louis XIV. Homberg promoted a radical vision for chymistry, no longer to be a mere adjunct to pharmacy, but the best means of understanding the natural world and its transformations. This study details how his novel, comprehensive theory of chymistry developed over twenty-five years from his observations and research results, revealing the dynamic between practice and theory formation. In their magnificent Palais Royal laboratory, Homberg and his patron Philippe II d’Orléans (the future Regent), also collaborated on uncovering the secret of gold-making, even though the administrators of the Académie forbade such studies. The French state also secretly pursued gold-making at the same time, by arresting and putting to work in the Bastille anyone who might solve the kingdom’s financial crisis through chrysopoeia. Although the Académie appeared to exile transmutation from the chymistry, its chemists actually pursued it secretly through the eighteenth century. Finally, the revival of Homberg’s methods and experiments in the 1770s provided results that would launch Lavoisier’s own “revolutionary” transmutations of chemistry.