Yes, Moses Maimonides was a Jew. Many erudite Jews would say that the scholar Maimonides was the greatest Jew of all times.
Here is a summary about Maimonides that we wrote a while back.
The contributions of Maimonides in the twelfth century (d. 1204) illustrate how deeply Judaism absorbed the impact of Islamic culture, even while rejecting its religion.
The Islamic cultural context of the Jews in the Middle Ages influenced the style and thought of Judaism. In the thought of Judah Halevi we see, for instance, how a rabbi used the style of philosophical discourse. Still, Halevi rejected the content of the philosopher's message. Reason and rationality, he said, were subservient to revelation, philosophy, and tradition. Some trace a relationship between Halevi and Abu Hamid al-Ghazali (d. 1111, author of the Incoherence of the Philosophers).
Maimonides presents a sharply contrasting approach. He was born in Cordova, Spain in 1135 C.E. In his early education and training he was the beneficiary of many generations of developed Jewish culture in Spain. Later, he was driven from his home by invading fanatical Almohades (Berber Muslims). When he settled in Egypt outside Cairo, he was already thoroughly versed in rabbinic and philosophical thought. In addition, he was a scientist and physician by profession and a widely respected personality in his own time.
Maimonides wrote several major intellectual works. His Book of Commandments enumerates the 613 commandments of Jewish law according to a well-conceived set of principles. In his great work, the Mishneh Torah, he reorganized all major aspects of talmudic law (halakhah) into 14 short and well-organized books.
This was a daring move. Maimonides took the Mishnah, Tosefta, and Talmud and extracted from them the main legal rulings. But in his books he gave only the decisions of the law, not the longstanding discussions and disputes of the talmudic rabbis. Maimonides began this work with a discussion of philosophical and ethical principles. He then turned to the remainder of the laws, such as those regarding holidays, civil laws, and sacrifices. But he did not present them according to the principles of arrangement used in the Mishnah. Instead, he reordered them in a new and more logical fashion.
His contemporaries were astonished that he dared to take such liberties. Furthermore, his own avowed explanation was outrageous to some of his colleagues. He said that his work was an attempt to replace the standard texts: with his books, students would not have to master the Talmud. Of course, such an undertaking caused much controversy during the decades that followed. Still, the clarity and utility of the Mishneh Torah overcame much of the opposition. Its language was in clear mishnaic Hebrew. Its approach to the content of Jewish tradition was systematic and rational. Yet in the end, his books did not replace the Mishnah and the rest of the authoritative literature of rabbinic Judaism. To this day they still serve as valuable supplements to and restatements of the major statements of the talmudic traditions.
Maimonides is also famous for his main philosophical work, The Guide of the Perplexed. The primary trait of the treatise is its difficult literary character, which helps to obscure the meaning of the writing. In contrast to the clarity and directness of the Mishneh Torah, The Guide is almost a secret writing. In content, the central themes of the book are based on the rationalist principles Maimonides learned from his philosophical predecessors within the Arabic culture. His Aristotelian approach builds on the legacy he encountered in the work of Avicenna (d. 1037) and Averroes (d. 1198) and especially al-Farabi.
The Guide uses some of the nonlegal sections of rabbinic interpretations to construct a view of man and of God based on rationalist principles. It addresses many topics on the philosophical agenda of the time, including the clash between reason and revelation; questions about the existence, unity, and incorporeality (lack of physical body) of God; God's actions, especially his creation of the world; the meanings and authority of law and prophecy: the distinction between good and evil; and the basis for the commandments of the Torah.
Although The Guide addresses these subjects, this book cannot be "read" by the average student. Maimonides wrote it to be a semi-secret work of speculation: he wanted only those initiated in the philosophy and the rabbinic thought of his time to be able to study it. Therefore, he wrote it in a kind of code by consciously making the organization of the book puzzling and by placing in it some outright contradictions. As a result, scholars down to the present have disagreed on many specific passages in the book and on the book as a whole.
What remains clear to the reader of The Guide is that Maimonides sought to harmonize the highest goals of philosophy with those of Judaism. Just as philosophers insisted that reason alone was sufficient to bring man into a direct encounter with God, so too did Maimonides argue that the well-trained mind within Judaism could also apprehend God through philosophical reason. Based on this understanding of the religion, Maimonides explained that the commandments of the Torah were most necessary for the average person, not for the philosopher. For ordinary Jews the commandments served as an alternate route to bring them closer to God. //repost from 2007 because of a story in the news today regarding someone from Teaneck who disrespected the great rabbi not too long ago in a way that ought not to be rehearsed here or anywhere ever again.//