When Maimonides’s “Guide of the Perplexed” appeared in southern France during the early 1300s, translated from Arabic into Hebrew, many in the Jewish community were outraged. This philosophical masterpiece, which Maimonides (c. 1138-1204) had completed in 1190 after three years of intensive toil, exalted the use of reason to an intolerable pitch. The “Guide” was unashamedly Aristotelian throughout in its presuppositions and (most of) its conclusions.

Maimonides had also employed Aristotelian methods and tenets in his treatment of halakah throughout his great “Mishneh Torah.” There he subjected the vast body of Jewish law contained in the “Mishneh” to rationalistic principles – arranging and codifying the myriad prescriptions enunciated over centuries – to form a coherent body of precepts. His famous “Thirteen Principles of the Faith,” a kind of creed stipulating what a Jew must believe in order to be called a Jew, represented an unprecedented dogmatic turn. French Jews placed both works under interdict and even had the “Guide” publicly burned.

The epitaph on Maimonides’s tombstone read, “from Moses to Moses there was none like Moses.” The first Moses was, of course, the prophet who spoke with God on Sinai, brought down the Tablets of the Law, and led the Jews out of exile in Egypt. Moses ben Maimon (or Musa ibn Maymun in Arabic) was the second. The honorific epitaph tells only part of the story. For this “second Moses” was not only a codifier of the law but a skilled physician, a master logician, a subtle exegete, an experienced judge, and a revered leader of the Jewish community; as if this weren’t enough, he was also one of the few medieval philosophers whose thought remains influential to this day.

Contrasts and paradoxes – some more apparent than real – abound in his career. Though he wrote his “Mishneh Torah” in Hebrew, he used Arabic for most of his other significant works – Arabic written in Hebrew letters, or “Judeo-Arabic.” The second Moses reversed the exodus, moving from Spain to Egypt, where he spent his most productive years in Fustat, earning his living as court physician to the Ayyubids, the dynasty founded in 1171 by Saladin. Rabbi Maimon, his father, fretted that he was lazy, but this lazybones produced a treatise on Aristotelian logic by the time he was 16. His commitment to Judaism was profound and unwavering, and yet he relied on Aristotle and such Muslim successors as al-Farabi, the “Second Teacher” (Aristotle was the “First Teacher”), to elucidate its tenets. In a posthumous twist of irony, his beloved son Abraham, whom he called “his only consolation,” in later life immersed himself in Sufism.

From Cordoba, where he was born, Maimonides and his parents fled Almohad intolerance, first to Fez, then, after a perilous sea-journey, to Acre, Jerusalem, Alexandria, and finally, Fustat, just two miles outside of Cairo. His loyalty to his birthplace never wavered; to the end of his life he signed himself “al-Qurtubi” (“The Cordovan” in Arabic). He also called his philosophy “Andalusian,” meaning its principles were derived from Aristotle and shared by all rationalists – Muslim, Christian, or Jewish. These principles led him to bring order and structure to the baffling complexities of Jewish law; they also reinforced his conviction that the truths of faith and of reason could not be at ultimate variance.

How write the life of such a polymath? To do so presupposes familiarity not only with Maimonides’s thought in such difficult areas as law, philosophy, theology, exegesis, the Bible, and Jewish custom, but also with the complex world of the Mediterranean in the 12th century. The late S.D. Goitein could have done justice to such a life. (He chose instead to write the biography of an entire vanished world in his six-volume masterpiece “A Mediterranean Society,” to which he devoted the last 20 years of his life.) The historian and surgeon Sherwin B. Nuland has now taken up the challenge with “Maimonides” (Schocken, 240 pages, $19.95).

Though not a medievalist (for which thanks be given), Dr. Nuland has some points of affinity with Maimonides. He is a physician and writes well and he has an obvious affection for his subject. He is agreeably modest, too, offering his brief book as his own “guide of the perplexed” to Maimonides. He winningly calls it “this Jewish doctor’s study of the most extraordinary of Jewish doctors.”

The merit of this compact life, the second in Schocken’s new series of “Jewish Encounters,” is that it offers a detailed sense of Maimonides’s achievements with a minimum of fuss. Dr. Nuland may have a scalpel to sharpen but he has no ax to grind. In his judgments, sometimes on tricky issues (such as Maimonides’s reported conversion to Islam), he is just and sensible. Best of all, he has a sure instinct for what’s important. He remarks, “If there is a single factor that characterizes [Maimonides’s] thought, it is the constant seeking to observe and interpret the world as it really is, and to find a place for his conclusions within the realm of received Law.” That is exactly right.

Maimonides’s rare clear-sightedness allied him as a physician with the extraordinary Abu Bakr al-Razi, one of the few medieval doctors to observe patients and their symptoms with his own eyes rather than rely blindly on Galen, and as a philosopher with both Aristotle and his Muslim successors, in particular Ibn Rushd. Maimonides detested al-Razi’s philosophical view point but he learned from his medical observations. He learned from al-Farabi too but repudiated his view that the world was eternal rather than created. This was not eclecticism but discernment, and in discernment Maimonides had few rivals.

Dr. Nuland conveys all this well, but Maimonides himself never comes alive in his pages. Dr. Nuland rarely quickens to his subject, even when discussing medicine. This is puzzling; of all the great medieval thinkers, Maimonides is one of the most immediate (as Goitein remarked, even his pronouncements in halakah often have a personal accent). Despite its many virtues, Dr. Nuland’s biography betrays a cribbed feeling as though the facts had all been expertly swotted up but not made fully his own.

At the opposite extreme stands Herbert Davidson’s “Moses Maimonides: The Man and His Work” (Oxford University Press, 567 pages, $49.95). If Dr. Nuland’s biography is brisk, Mr. Davidson’s is heavy weather. Clearly the product of a lifelong passion, his monograph documents and analyzes almost everything known about the medieval thinker. Each page teems with learned references: Sources in both Arabic and Hebrew are plumbed, and there appears to be little that Mr. Davidson hasn’t read.

Maimonides is wonderfully quotable, and both biographers avail themselves of his pithy remarks. Mr. Davidson does better in evoking some sense of the man, no doubt because he could read the originals. When Maimonides remarks, “I forgive everyone who speaks ill of me through stupidity,” the quote isn’t only amusing but apt, and we get a feeling for the man who uttered it. (At other moments, however, Mr. Davidson intrudes himself rather too much, as when – it is perhaps an attempt at wit – he chides Maimonides for lacking “gender sensitivity.”)

Some reports claim that Maimonides converted to Islam, under duress, while still in Spain; an epistle ascribed to him defends Jews who were compelled to resort to such stratagems. Dr. Nuland quotes his remark: “If a man asks me, ‘Shall I be slain or utter the formula of Islam?’ I answer, ‘Utter the formula and live.’ ” And yet, as Mr. Davidson is at pains to emphasize, how bad could the persecution have been, since in one epistle Maimonides had the temerity to describe the Prophet Muhammad as “meshuggah”?

These and other Maimonidean puzzles probably won’t be resolved soon, if ever. What remains, however, is the amazing and enduring work, both in law and in philosophy. I can’t claim that reading or teaching “The Guide of the Perplexed,” especially in the lucid translation by Shlomo Pines (1974, but still in print), has lifted any of my own perplexities. If anything, his book has intensified their entanglements. At the same time, however, I like to think that Maimonides has somehow rendered my perplexities fruitful, and what more could one hope for from a book?

eormsby@nysun.com