This book breaks new ground in the study of Judaism, in philosophy, and in comparative ethics. It demonstrates that the assumption that Judaism has no natural law theory to speak of, held by the vast majority of scholars, is simply wrong. The book shows how natural law theory, using a variety of different terms for itself throughout the ages, has been a constant element in Jewish thought. The book sorts out the varieties of Jewish natural law theory, illuminating their strengths and weaknesses. It also presents a case for utilising natural law theory in order to deal with current theological and philosophical questions in Judaism’s ongoing reflection on its own meaning and its meaning for the wider world. David Novak combines great erudition in the Jewish tradition, the history of philosophy and law, and the imagination to argue for Judaism in the context of current debates, both theoretical and practical.