Dear Professor Dawkins,
I'm not sure if words can express how thankful I am to you for your books. When I began having doubts about my faith, I decided to pick up The God Delusion to see what you had to say. The book caused quite a stir, after all, so I wanted to find out for myself what all the fuss was about.
What I found in The God Delusion was far greater than I could have expected. It was a truly liberating experience, and I am now proud to call myself an atheist. I could ramble on for pages and pages, but I think I'll spare you that and simply say, "Thank you!"