Between the years 1643 and 1649, Princess Elisabeth of Bohemia (1618â€“80) and RenĂ© Descartes (1596â€“1650) exchanged fifty-eight lettersâ€”thirty-two from Descartes and twenty-six from Elisabeth. Their correspondence contains the only known extant philosophical writings by Elisabeth, revealing her mastery of metaphysics, analytic geometry, and moral philosophy, as well as her keen interest in natural philosophy. The letters are essential reading for anyone interested in Descartesâ€™s philosophy, in particular his account of the human being as a union of mind and body, as well as his ethics. They also provide a unique insight into the character of their authorsÂ and the way ideas develop through intellectual collaboration.Philosophers have long been familiar with Descartesâ€™s side of the correspondence. Now Elisabethâ€™s lettersâ€”never before available in translation in their entiretyâ€”emerge this volume, adding much-needed context and depth both to Descartesâ€™s ideas and the legacy of the princess. Lisa Shapiroâ€™s annotated editionâ€”which also includes Elisabethâ€™s correspondence with the Quakers William Penn and Robert Barclayâ€”will be heralded by students of philosophy, feminist theorists, and historians of the early modern period.