This chapter explores the medieval genre of sifrut ha-musar (ethical literature), which has largely been ignored in the recent burgeoning of the field of Jewish ethics. This neglect is attributed to the fact that the genre does not call halakhah into question, as does Jewish ethics generally, particularly through the notion of lifnim mi-shurat ha-din (supererogation), that one must act beyond the letter of the law. But this does not mean that musar is non-ethical; rather, its purpose was to “harmonize the spirituality of God with the values guiding his worship.” This spiritualization of Jewish ritual and culture generated creativity for nearly a thousand years around the Jewish world, first in Islamic contexts and then climaxing in Christian milieus.