My first exposure to C. S. Lewis was through his classic science fiction tale, Out of the Silent Planet. I read it my sophomore year at Washington Bible College when my dormitory room was on the northeast side of the building facing some pine trees and the road which rounded down the hill from the main entrance of the college. I still remember those hours when I would sit back in the desk chair and rest my feet on the desk and read Lewis' story about a man from Earth ("the silent planet") to the planet Malacandria. The book is rich in description and the experience of reading it has stayed with me for many years.
And he is the author of the Narnia books as well as many other books on theological ideas. I loved reading him.
As I wandered around the internet I found an old interview he gave to the BBC that is related to his book "Mere Christianity". It features Lewis' gift of being able to explain theological concepts using everyday examples. I especially love his explanation of the eternal nature of God to our finite existence: "... [God] has infinity in which to listen to the split second of prayer..."