Sefer miẓvot gadol (Semag) by the French Tosefist R. Moses of Coucy was a most influential halakhic work in medieval times. Originally titled Sefer ha-miẓvot (The Book of Commandments), it was written in northern France in the first half of the thirteenth century and in many ways reveals the influence of Maimonides' Mishneh Torah. Indeed, to understand R. Moses of Coucy's legal project properly, it is important to comprehend the availability of Mishneh Torah in Europe at the time. Whereas Maimonides completed his Mishneh Torah circa 1180, the work seems not to have reached the study halls of the French Tosefists before 1200. In this article, I explain R. Moses' purpose and program in writing his Sefer ha-miẓvot, examine the format he chose, and clarify who his presumptive reader, or readers, may have been.