The TaRYaG count-the traditional enumeration of the 613 commandments contained in the five Mosaic books (Torah)-holds a prominent place in Jewish thought. The tradition is based on an aggadah found in the Babylonian Talmud and, with some variants, in Midrash Tanhuma. No one did more to see this count achieve its place of importance than Moses Maimonides, who, in his Sefer ha-Mitsvot, methodically crafted a list with the intent of having it serve as an outline for his upcoming Mishneh Torah, the most comprehensive code of law in Jewish history. In the first half of this work, Friedberg investigates Maimonides' methods and reasoning and arrives at a new and innovative reason for his interest in the TaRYaG count. Friedberg then continues, carefully examining the language used for presenting commandments in the Mishneh Torah, which suggests to him new dimensions in Maimonides' legal theory.

Rabbinic tradition has it that 613 commandments were given to Moses on Mount Sinai, but it does not specify those included in the enumeration. Maimonides methodically and artfully crafts a list of 613 commandments in a work that serves as a prolegemenon to the Mishneh Torah, his monumental code of law. This book explores the surprising way Maimonides put this tradition to use and his possible rationale for using such a tradition. It also explores many of the philosophical and ethical ideas animating the composition of such a list. In the book's second half, Friedberg examines the manner by which Maimonides formulated positive commandments in the Mishneh Torah, leading him to suggest new dimensions in Maimonides' legal theory.