Moses Maimonides (also known as the Rambam, which is an acronym for Rabbi Moshe ben Maimon) is generally recognized as the greater Jewish scholar and thinker of all times. Born in Cordovia, Spain in 1135, Maimonides was a physician, philosopher, and Biblical and Talmudic commentators par excellence. He wrote a treatise on medicine, an important work of philosophy, a law code, and copious commentaries on the Bible and Talmud.

When Maimonides was still a young boy, the Almohads conquered Cordova and the family left Spain. They wandered from town to town for nearly a decade, finally settling in Fez in northern Africa in 1160, but Fez proved no safer than Cordova. Maimonides and his family fled Fez for Acco in the Land of Israel, where they stayed for but a few months, before venturing on to Egypt. In Egypt, Maimonides supported himself and his family by serving as a court physician to the sultan, ruler of Egypt. He studied and wrote, and served as a rabbinic authority for communities in Egypt and well beyond, receiving their questions and proffering halakhic answers and advice.

The Rambam write his great legal code, the Mishneh Torah, during this period. While the laws that constituted halakhah were contained throughout the Talmud, they were not presented in a categorical fashion, and without enormous knowledge and background, one could not locate them with ease. What is more, the focus of Talmud is not precise legal decisions, but rather the discussions that lead to them. Maimonides presented the particulars of halakhah in a clear, organized fashion, written in beautiful, elegant Hebrew. The book, comprising 14 volumes (which, in Hebrew is written "yod-daled" thus giving the code its nickname, the Yad), is well organized and easy to use. It infuriated the rabbinical authorities of the day, who could not imagine the audacity of quoting a law without the rabbinic argument entailed in it. What was more, they feared that unqualified people would declare themselves experts on law, dispensing "decisions," without the knowledge and expertise to understand the use of precedent or appreciate the subtleties and nuances of legal thinking. In truth, Rambam's Mishneh Torah was a revolutionary work, and its simple, beautiful Hebrew language made it readily accessible to virtually everyone. All Jewish law codes written after the Yad use the same organizing principles and make reference to it.

During this time, Maimonides authored his great philosophical treatise, Moreh Nevuchim (Guide for the Perplexed), as well. Written in the Arabic of the day, Moreh Nevuchim is a far more recondite text which expounds Maimonides philosophy of Judaism, steeped in Aristotelian thought, and influenced by the Muslim philosophers Avicenna and al-Farabi. Maimonides underlying purpose in writing Moreh Nevuchim was to reconcile Judaism with the central tenets of Aristotelian thought. Toward this end, he discuss the importance and integrity of logic, mathematics, metaphysics and science, in discerning truth, and demonstrates that Torah operates according to these principles. The Moreh Nevuchim was translated into Hebrew by members of the ibn Tibbon family, making it accessible to a larger audience of Jews.

After Maimonides' death in 1204, his Moreh Nevuchim was widely circulated in Europe where it causes quite a stir. It appeared that Maimonides did not belief in resurrection of the dead and considered prophecy a function of intellectual capacity. Those who promoted his ideas and those who were his detractors fought bitterly with one another until Dominican inquisitors in France burned copies of the Moreh Nevuchim, galvanizing both sides in opposition to book burning. There is little doubt that Maimonides foresaw the controversy that would surround his work, because in the introduction, he wrote that he had hidden truths among necessary falsehoods. This further served to protect him against accusations of heresy: How could one be certain which were his "truths" and which were his "falsehoods." To this day, people debate what Maimonides truly believed.

In his commentary to the Mishnah, Maimonides wrote that there are thirteen statement of Jewish faith. While Judaism had always shied away from credal statement, outside threats from the Karaites, and influence from Muslim culture, may have contributed to Maimonides formulation. The Thirteen Statement are immortalized in the words of the Yigdal, a hymn sung in synagogue on Erev Shabbat (Friday evenings). They are:

The Rambam is also lovingly remembered for his teachings on tzedakah (righteousness and justice), in particular for delineated the eight levels of giving, each higher than the previous. They eight rungs of tzedakah are: