A battle has been joined for the soul of Narnia. Not the battle between Aslan the good lion and the diabolical White Witch – the outcome of that war is known to every reader of “The Lion, the Witch and the Wardrobe,” the first book in C.S. Lewis’s classic children’s series, “The Chronicles of Narnia.” No, the new struggle to determine the fate of Lewis’s fantasy world is being waged in movie theaters and bookstores, and it lacks the reassuring clarity of Lewis’s Christian allegory.

Aslan, as all adult readers will quickly recognize, is Lewis’s version of Jesus, an all-powerful deity who submits to torture and death in order to redeem the world. In Narnia, as in all children’s books (and most religious myths), good and evil are impossible to mistake, and the final triumph of the right side is guaranteed. The conclusion of the seven-book series, in “The Last Battle,” offers a vision of judgment straight out of the Book of Revelations: Aslan sends evildoers to hell and brings good children with him to paradise.

When the new Disney movie of “The Lion, the Witch and the Wardrobe” comes out this week, however, it will be harder to separate the sheep from the goats. Are the movie’s producers and marketers helping to spread the magic of Narnia, winning a new generation of children to Lewis’s vision, half a century after the books were first published? Or are they ruthlessly exploiting Lewis, turning his poetically original, morally serious books into just another money-spinning Hollywood franchise? Are readers who listen with concern or regret to the advance rumblings of the Disney machine – the previews, profiles, advertisements – to be considered noble purists? Or are they mere nostalgists, wanting to preserve the Narnia books in the amber of childhood – or worse, sectaries, fussing over Lewis’s lore the way others do over “Star Wars” or Sherlock Holmes?

However you feel about the Narnia onslaught, there is no avoiding it. Visit any big bookstore and you will discover a whole new display of Narnia products, proliferating to fill every market niche. There are the seven Narnia books themselves, now available as disposable paperbacks, illustrated paperbacks in a Full Color Collector’s Edition, a boxed set, a single-volume hardcover, and a coffee-table-sized gift edition. There are official movie tie-in books like “Narnia: Behind the Wardrobe,” bristling with photos and production notes. And there are the inevitable spin-offs: a 100-piece jigsaw puzzle (which resolves into an image from the movie, naturally, not one of Pauline Baynes’s classic illustrations),a Milton Bradley board game, a glossy calendar.

Unless things go badly wrong, Narnia is going to make a lot of money for a lot of people. And not just Disney and Walden Media, the producers of the new film. HarperCollins, which holds the rights to the books first published by Lewis between 1950 and 1956, is poised to turn Narnia into a goldmine, like Harry Potter for Bloomsbury and Tolkien’s Middle Earth for Houghton Mifflin. Smaller publishers, too, are on the bandwagon.

In addition to the novels themselves, there is a whole library of studies and companions, which appeal to two distinct audiences. For the fans and trivia-hoarders, there are books like Paul Ford’s “Companion to Narnia” and Colin Duriez’s “The C.S. Lewis Chronicles,” encyclopedias of character names, plot points, and Lewisian milestones. For Christians and spiritual seekers, there are books that treat the Chronicles of Narnia as the world’s longest tract: titles like “Aslan’s Call: Finding Our Way to Narnia” (whose cover promises “In Aslan We Find Christ”) and “The Heart of the Chronicles of Narnia: Knowing God Here by Finding Him There.” Between the media conglomerates and the small religious houses, that Narnia display could be in the bookstore well into the next decade.

Looking at the heaped offerings, I was reminded of a particular Narnian episode. In “The Magician’s Nephew,” written several years after “The Lion, the Witch and the Wardrobe” but designed as a prequel to the whole series, Lewis offers a Narnian translation of the Book of Genesis. By a series of cosmic accidents, a party of late Victorian Britons come to be present at the creation of Narnia, as Aslan literally sings the new world into existence. It is one of Lewis’s most metaphysically resonant passages, more moving than the fussily allegorical Apocalypse of “The Magician’s Nephew,” but Lewis does not miss the opportunity to deliver a homily at the same time.

One of the English intruders, the sneaky magician Uncle Andrew, notices that, in the enchanted fertility of Narnia’s first hours, anything dropped into the ground immediately starts to grow: a piece of metal becomes a lamppost, a toffee becomes a candy tree. To Andrew, who Lewis has tagged from the start as a selfish schemer, this seems like a perfect opportunity to make a profit: “The commercial possibilities of this country are unbounded. Bring a few bits of old scrap iron here, bury ’em, and up they come as brand new railway engines, battleships, anything you please. They’ll cost nothing, and I can sell ’em at full prices in England. I shall be a millionaire.”

Lewis could not have predicted the fate of his own creation more accurately. He, like Aslan, sang Narnia into being; then some corporations came along, starting digging up the fertile soil of Lewis’s imagination, and out sprang a whole family of spin-offs, tie-ins, and ancillary profit centers. If this seems more unpleasant in Lewis’s case than in the case of J.K. Rowling, it is not just because the literary level of the Narnia books is so much higher. It is because so much of Lewis’s moral message is devoted to the dangers of exploitation – commercial, industrial, ecological – and the corresponding virtues of pure imagination. That Narnia itself could be so successfully exploited, even in the gentle guise of a Disney movie, proves that Lewis’s critique of our society has lost none of its point or power.