Clyde S. Kilby joined the faculty of Wheaton College in 1935 at the age of 33 as an assistant professor of English and dean of men.

In 1943 Kilby read a new book published by C. S. Lewis, entitled The Case for Christianity, which changed the course of his life. It was based on two series of broadcast talks Lewis had given for the BBC and was later published as the first two sections of Mere Christianity. “I . . . read it right through feeling almost from the first sentence that something profound had touched my mind and heart.” It was like discovering “something bottomless,” and he was captivated by “the depth and freshness of his observations and the permanency of his expression.”