As I walked away from New Buildings, I found the man that Lewis had called "Tollers" sitting on one of the stone steps in front of the arcade.

"How did you get on?" he asked.

"I think rather well. I think he will be a most interesting tutor to have."

"Interesting? Yes, he's certainly that," said the man, who I later learned was J. R. R. Tolkien. "You'll never get to the bottom of him."

Over the next twenty-nine years, author George Sayer's first impression about C. S. Lewis proved true. He was interesting; but he was more than just that. He was a devout...