A bright and sensitive British boy turned by public-school sadism into a warped, morbid, stammering sexual pervert. It sounds like the usual story. What was special about Lewis was that, throughout it all, he kept an inner life. Joy kept him alive—and it is possible that the absence of happiness allowed an access of joy. When he served on the Western Front, in 1917, he got what every soldier wanted—an honest wound honestly come by but bad enough to send him home. Still, he saw the trenches as they really were, and though he chose largely to forget, and tried to deprecate the importance of “the horribly smashed men still moving like half-crushed beetles,” he admitted, in later years, that he had had nightmares about it for the rest of his life.

Oxford always seemed like joy to escapees from public schools; add the Western Front, and it must have seemed like something close to paradise. After Lewis’s first long residence there, upon his departure from the Army, in 1918, he never left Oxford again, except, at the end, for Cambridge. He took a first in classics, and then made a decision, slightly daring in those days, when teaching English literature seemed as swinging as teaching media studies does now, to become a tutor in English; he soon became a fellow in English at Magdalen College. (He also took up with a much older married woman, with whom he had a long affair that may have had a sadomasochistic tinge.)

Jacobs is a bit touristy about Magdalen’s charms; Wilson is much better, tartly and accurately describing how the system of tutorials, seemingly so seductive—an essay delivered each week by the pupil, and analyzed and critiqued by the tutor—helps turn the tutors, from sheer exhaustion and self-protection, into caricatures of themselves, rather as the girls in a lap-dance club take on exotic names and characters. Lewis, the sensitive and soft-spoken young hiker, took on the part of a bluff, hearty Irishman, all tweed and pipe. It is this Lewis who became an Oxford legend, smoking in darkened rooms and holding “Beer and Beowulf” evenings in his rooms. He held to the narrow anti-modern curriculum then in place at Oxford, and befriended a young philologist named J. R. R. Tolkien, whose views on teaching English were even more severe than Lewis’s: Tolkien thought that literature ended at 1100.

Lewis had a reputation as a tough but inspiring teacher, and, reading his letters, one can see why. His literary judgments are full of discovery; his allegiance to a dry, historical approach in the university didn’t keep him from having bracingly clear critical opinions about modern books, all of them independent and most of them right. He got the greatness of Wodehouse long before it was fashionable to do so, appreciated Trollope over Thackeray, and could admire even writers as seemingly unsympathetic to him as Woolf and Kafka. He was a partisan without being a bigot.

It was through the intervention of the secretive and personally troubled Tolkien, however, that Lewis finally made the turn toward orthodox Christianity. In company with another friend, they took a long, and now famous, walk, on an autumn night in 1931, pacing and arguing from early evening to early morning. Tolkien was a genuinely eccentric character—in college, the inventor of Lothlorien played the part of the humorless pedant—who had been ready to convert Lewis for several years. Lewis was certainly ripe to be converted. The liberal humanism in which he had been raised as a thinker had come to seem far too narrowly Philistine and materialist to account for the intimations of transcendence that came to him on country walks and in pages of poetry. Tolkien, seizing on this vulnerability, said that the obvious-seeming distinction that Lewis made between myth and fact—between intimations of timeless joy and belief in a historically based religion—was a false one. Language, and the consciousness it reflected, was intrinsically magical. One had to become religious to save the magic, not to be saved from it. (It was, ironically, the same spirit in which the children of the nineteen-sixties felt that the liberal humanism in which they had been raised failed to account for the intensities of another kind of trip—and that led them, too, to magic, and to Lewis and Tolkien.) All existence, Tolkien insisted on that night ramble, was intrinsically mythical; the stars were the fires of gods if you chose to see them that way, just as the world was the stories you made up from it. If you were drawn to myth at all, as Lewis was, then you ought to accept the Christian myth just as you accepted the lovely Northern ones. By the end of the walk, Lewis was, or was about to become, a churchgoer.

This was a new turn in the history of religious conversion. Where for millennia the cutting edge of faith had been the difference between pagan myth and Christian revelation, Lewis was drawn in by the likeness of the Christian revelation to pagan myth. Even Victorian conversions came, in the classic Augustinian manner, out of an overwhelming sense of sin. Cardinal Manning agonized over eating too much cake, and was eventually drawn to the Church of Rome to keep himself from doing it again. Lewis didn’t embrace Christianity because he had eaten too much cake; he embraced it because he thought that it would keep the cake coming, that the Anglican Church was God’s own bakery. “The story of Christ is simply a true myth,” he says he discovered that night, “a myth working on us in the same way as the others, but with this tremendous difference that it really happened.”

It seemed like an odd kind of conversion to other people then, and it still does. It is perfectly possible, after all, to have a rich romantic and imaginative view of existence—to believe that the world is not exhausted by our physical descriptions of it, that the stories we make up about the world are an important part of the life of that world—without becoming an Anglican. In fact, it seems much easier to believe in the power of the Romantic numinous if you do not take a controversial incident in Jewish religious history as the pivot point of all existence, and a still more controversial one in British royal history as the pivot point of your daily practice. Converted to faith as the means of joy, however, Lewis never stops to ask very hard why this faith rather than some other. His favorite argument for the truth of Christianity is that either Jesus had to be crazy to say the things he did or what he said must be true, and since he doesn’t sound like someone who is crazy, he must be right. (He liked this argument so much that he repeats it in allegorical form in the Narnia books; either Lucy is lying about Narnia, or mad, or she must have seen what she claimed to see.) Lewis insists that the Anglican creed isn’t one spiritual path among others but the single cosmic truth that extends from the farthest reach of the universe to the house next door. He is never troubled by the funny coincidence that this one staggering cosmic truth also happens to be the established religion of his own tribe, supported by every institution of the state, and reinforced by the university he works in, the “God-fearing and God-sustaining University of Oxford,” as Gladstone called it. But perhaps his leap from myth to Christian faith wasn’t a leap at all, more of a standing hop in place. Many of the elements that make Christianity numinous for Lewis are the pagan mythological elements that it long ago absorbed from its pre-Christian sources. His Christianity is local, English and Irish and Northern. Even Roman Catholicism remained alien to him, a fact that Tolkien much resented.

If believing shut Lewis off from writing well about belief, it did get him to write inspired scholarship, and then inspired fairy tales. The two sides of his mind started working at the same time and together. His first important book, and his best, is “The Allegory of Love,” a study of epic poetry that Lewis began writing soon after his conversion. It is full of enthusiasm for and appreciation of the allegorical epics of Ariosto, Tasso, Spenser, et al.—but it also makes a profound historical argument about the literary imagination. Until the time of Tasso and Ariosto, he points out, writers had two worlds available to them: the actual world of experience and the world of their religion. Only since the Renaissance had writers had a third world, of the marvellous, of free mythological invention, which is serious but in which the author does not really believe or make an article of faith. In Ariosto, Lewis found the beginnings of that “free creation of the marvelous,” slipping in under the guise of allegory: