Gender concepts have been hotly contested for more than 2500 years. For orientation in these disputes, it is important to know their traditions as well as conquered alternatives. Simone de Beauvoir's concepts of "existence" and "sexual differentiation" and Hannah Arendt's concept of plurality are crucial touchstones for reconstructing philosophical category theory and its entanglements with gender theorems. The book seeks out gender discourses in the history of philosophy from antiquity to modernity, makes the underlying concepts visible and reveals continuities and breaks within them.