I picked up the first in the series as a young child, a very ready mind, since my first book of any length was having The Hobbit read to me as a child. I didn't know that Tolkien and Lewis used to sit over a table in an Oxford pub discussing literature. I didn't know Lewis specialized in Christian allegory. What I did learn is that the tale of Jesus, told as the tale of a lion king's self-sacrifice is incredibly affecting to a child otherwise oblivious to Christian allegory. I failed to see the self-sacrifice of a king turning so quickly tragic in the few crucifixes I'd seen.
But I never read any of the other books. Something about didactive allegory was too cloying to my yound mind. It was like Turkish delight, which sounds sticky and dangerous but is really quite bland in person. It seems Tolkien never quite took to the restrictive vision of Lewis either.
Finally, I've visited the very beautiful little town where Lewis spent his vacations. It has a spectacular ruin of a stonehenge mansion, British folly style, high on the slope of a lush and empty cliff. I remember wondering why Lewis would want to find secret doors to a different land in a place like this. Was he living in a mansion like it and couldn't go back to that part of Ireland, where so many English writers discovered their magic?