I often say that almost all of my theology comes from reading "The Narnia Suite," which I read for the first time at the age of eight, and more than a dozen times thereafter. I was particularly taken with The Last Battle, in which some people are very surprised indeed to learn that those they thought wouldn't be admitted into Aslan's Land because they fought on "The Wrong Side" of the aforementioned last battle, were in fact instantly admitted because it was their intention and their heart which was judged.
When I was a little older, someone gave me a copy of "The Screwtape Letters," and I have read it probably a dozen or more times over the years as well. Brilliant, allegorical, hilarious in parts, and filled with gentle wisdom, it is a theological masterpiece. I recall the first time I the letter in which one devil brags that he will soon win his first soul for the devil because although the man continues to pray, he doesn't believe what he says any longer. The older, wiser devil releases a stream of invective and explains the younger devil is an idiot, because doesn't the know that "those are the prayers that God loves best!?" How relieved I felt, as a young person, that there was a possibility God might still embrace me, even with all my doubts. Just one of the many gifts Lewis's work offers to those of us searching for a deeper relationship with God.