"I wish your project heartily well," wrote C. S. Lewis to Christianity Today, "but can't write you articles." Carl F. H. Henry, founding editor of the magazine, had in 1955 invited Lewis to contribute to the magazine's first issue. Lewis declined. Henry was not, as the saying goes, "a day late and a dollar short." He was over a decade late, and no dollar amount would have mattered, as Lewis gave the lion's share of his royalties to charity.

There was a time when Lewis would have said yes: namely, when Nazi soldiers marched into Poland and threatened the stability of the world. Adolf Hitler's influence on Lewis's apologetics is an irrefutable fact. The Führer's evil campaign paved the way for the clear-speaking Lewis to engage listeners of the British Broadcast Service. Even as bombs fell over London, Lewis's baritone voice boomed on radios across Europe. His evangelistic approach was tailormade for men at war.

Thus, Mere Christianity was b orn in the fullness of time. Published in 1952, the classic was taken from transcripts of his broadcasts from the early 1940s. By the time the book was available in print, Lewis was already changing his approach. As Solomon said, "There is a time for war and a time for peace." Lewis modified his methods for both.

"But supposing that by casting all these things into an imaginary world," Lewis later said of the power of fiction to present truth, "could one not thus steal past those watchful dragons?" Lewis thought so. Thus, his writing career focused on smuggling theology behind enemy lines. The enemies Lewis now faced were comfort and post-war apathy. To battle both, he would engage his readers' imagination.

It would be easy for a young apologist to miss the brilliance of Lewis's creativity. Our day is marked by both war and peace, calling for a multifaceted and flexible line of attack. Herein Lewis's life and witness provide many examples for evangelists today. While Lewis's articulation of the gospel took different paths, they all led to Christ. In so doing, he was able to take aim at both the head and the heart.

A "C. S. Lewis for the 21st century" must offer his apologetics in both war and peace. As Lewis told one group of youth workers shortly before the end of World War II, "That is why we apologists take our lives in our hands and can be saved only by falling back continually from the web of our own arguments . . . from Christian apologetics into Christ himself." If Lewis was falling back from his arguments, it could only mean one thing: Aslan was on the move.

Before introducing the world to The Chronicles of Narnia, Lewis publish ed Miracles in 1947. It was his last straightforward defense of the gospel. Lewis told his friend and biographer George Sayer that he would never again write another "book of that sort." And he didn't. From that point forward, he published primarily fictional, devotional, and biographical material. His passion for explaining and defending the Christian faith could now best be found in a magical world of talking animals.

That's why he declined Henry's request to write articles about Christian doctrine. As Lewis told Henry, "My thought and talent (such as they are) now flow in different, though I trust not less Christian, channels, and I do not think I am at all likely to write more directly theological pieces. The last work of that sort which I attempted had to be abandoned. If I am now good for anything it is for catching the reader unawares—thro' fiction and symbol. I have done what I could in the way of frontal attacks, but I now feel quite sure those days are over."

The abandoned work he referenced to Henry is likely Letters to Malcolm: Chiefly on Prayer, published posthumously in 1964. It didn't come together until it was set in the context of an imaginary conversation with a fictional friend. It also appears that Lewis opted for a less straightforward apologetic approach following a debate with female philosopher G. E. M. Anscombe at the Socratic Club on the topic of miracles, a debate after which some felt Anscombe was the clear winner. And there are other examples in his public addresses and personal correspondence where Lewis explained with transparency how defending the gospel had taken its toll.

Ultimately, the fall of the Third Reich brought with it an end to Lewis's direct apologetic. And though Britain was at peace, Lewis continued to fight another battle until his death in 1963. Like the deep magic of Narnia, this battle was not with flesh and blood but with powers and principalities. From wartime talks to talking fauns, his excellent life was committed to the advancement of the gospel. Though dead, yet still he speaks.

Dan DeWitt is the dean of Boyce College, the undergraduate school of The Southern Baptist Theological Seminary in Louisville, Kentucky. He blogs at Theolatte.com.