In this book, Samuel Lebens takes the three principles of Jewish faith, as they were proposed in the fifteenth century by Rabbi Joseph Albo, and seeks to scrutinise and refine them with the tool-kit of contemporary analytic philosophy. What could it mean for a perfect being to create a world out of nothing? Could such a world be anything more than a figment of God's imagination? What is the Torah, and what must a person believe before it would make sense to treat it as Orthodox Judaism does? What does Judaism expect from a Messiah, and what would it mean for a world to be redeemed? These questions are explored in conversation with a wide array of Jewish sources - the Bible, Philo, the Rabbis of the Mishna and Talmud, the medieval rationalists and mystics, the Hassidim, and more, with an eye towards diverse fields of contemporary research, such as cosmology, logic, the ontology of literature, and the metaphysics of time. The Principles of Judaism articulates the most fundamental axioms of Orthodox Judaism in the vernacular of contemporary philosophy.