Have you read his auto-biography
Surprised by Joy or any biographies about him? If not - I suggest you should. That'll give you answers to your question.
You can find information and books both by and about Lewis on this site, in areas like bio, works, papers, other resources and of course the bookstore.
By the way, one of the obvious things that inspired Lewis, clearly - because he wrote so much about it, was his Christian faith.