From ancient times to the present day, utopian social ideas have made the unity of humankind a central concern. In this volume, scholars of ancient history, early Judaism, biblical studies, and early Christianity explore the themes of unity and oneness in important classical, biblical, early Jewish, and early Christian texts. The contributions show that the early Christians, with their inherited Jewish, Greek, and Roman traditions, were remarkable in their articulation of the ideal of oneness and in their attempts to put it into practice.