This book offers a selective, typological overview of Jewish perspectives on the belief in God's oneness. To achieve this, the author divides the history of Judaism into four phases - biblical, rabbinic, medieval, and modern - and presents diverse models for understanding the reality of divine oneness within each phase. These models not only offers insight into different perspectives on the topic but also illuminate diverse layers of polemical discourse in the Jewish tradition, whether internal or in dialogue with other religions and worldviews. In addition, the author invites readers to consider how to think about the plurality of the perspectives at hand, and if and how such meta-reflection can enrich the lives of contemporary readers, Jewish and non-Jewish alike. No prior knowledge of Judaism is necessary.