What if the feminine has played a far more profound role in Western thought than we have imagined? This volume offers a bold new account of feminine principles as metaphysical forces of unity and primordial undifferentiation. Bringing together leading scholars of philosophy and religious studies, it traces the diverse forms and remarkable transformations of feminine principles across an extraordinary intellectual landscape: from Hesiod, Plato, and Neoplatonism to Kabbalah, Gnosticism, Christianity, Renaissance philosophy, and Jung. Challenging familiar approaches to femininity in the West, the volume uncovers deep continuities and striking transformations across centuries, opening a new field of inquiry into the metaphysical significance of feminine principles in Western intellectual history.