Undertaking the classic question of the relationship of Islam to Judaism, Geiger begins his treatment with the intertwined questions of what Islam wishes to do, is able to do, and is permitted to do with Judaism. Concepts and opinions such as faith beliefs, moral and legal regulations, and concepts of life are all considered as they moved from Judaism to Islam. A well-regarded early work in the field of comparative religions, Geiger’s work is not to be missed by anyone with an interest in Judaism and its relationship to Islam.