Rabbi Moshe ben Maimon (known as Rambam or Maimonides) was the acknowledged leader of Spanish Jewry during the twelfth century, and is today widely recognized as one of the leading Torah authorities in all of Jewish history. Sefer haMitzvoth (Book of the Commandments) was one of his most significant works. In it, he drew upon the vast spectrum of rabbinic literature as he enumerated and explained the most fundamental teachings of Judaism--each and every one of the taryag mitzvoth, the 613 commandments. At the same time, he clarified the principles used in determining which precepts were to be included in this number.