Lewis was an amazing man. A more serious scholar and thinker than most who know about him today would probably expect, a brilliant writer, and he did things like respond to all of his fan mail and give away the lion's share (pardon the pun) of his works' profits.
He gave away most of his book royalty income for several reasons: 1. He was a Christian. 2. For most of his life he was a bachelor and didn't need much to live on. 3. Magdalen College, Oxford (and later Cambridge University) provided him accomodations as well as a scholarly income from his professorship.
He's also probably the greatest (or at least the most popular) Christian author in history. I see other Christian teachers living in luxury and while I don't doubt their faith in Jesus I can't sit at their feet while they're not bearing fruit themselves.
