A man who liked C. S. Lewis's Screwtape Letters went on to read Mere Christianity-and was infuriated. He wrote the author a scathing letter.

Lewis's response, in longhand, shows a master evangelist at work:

"Yes, I'm not surprised that a man who agreed with me in Screwtape . . . might disagree with me when I wrote about religion. We can hardly discuss the whole matter by post, can we? I'll only make one shot. When people object, as you do, that if Jesus was God as well as man, then he had an unfair advantage which deprives him for them of all value, it seems to me as if a man struggling in the water should refuse a rope thrown to him by another who had one foot on the bank, saying, 'Oh, but you have an unfair advantage.' It is because of that advantage that he can help. But all good wishes. We must just differ; in charity I hope. You must not be angry with me for believing, you know; I'm not angry with you."

What impresses me about that exchange is the light touch. Lewis acknowledges the ...