Dear Dr. Dawkins,
From the ages of 17 to 20 I was a tormented Christian. I believed (i.e. was too scared to not believe) just enough to fear reading anything that might cause me to doubt Christianity. I was in an endless loop of doubt caused by the obvious absurdities of the bible followed by extreme fear of hell. In exasperation I asked my sister for some material, something to combat the fear that dominates an ignorant mind. She gave me The Selfish Gene. I read it and was deconverted. It didn't take more than the first few chapters, just enough fodder to give me the confidence to question. Once one accepts the possibility that the bible or whatever MAY be false, plus Darwin, the Hubble space telescope, etc, it doesn't take a genius to see that Jesus is about as credible as The Wizard of Oz.
The Selfish Gene motivated me to study biology and I've been working in biotech for last 11 years working on DNA sequencers (Moore's Law of DNA). My favorite book of yours is The Extended Phenotype, it's better than the best science fiction.
Thanks so much for your books, they have truly changed my life.