Charmed by the simple parable, and entirely missing the message of Christianity behind it, I devoured the other 6 books in the order they should be read. However, years have passed and only LWW, The Magician's Nephew (which explains the birth of Narnia, and how the wardrobe came to be made), The Horse and his boy and fragments from the The Last Battle remained in my mind. When I found the LWW was being made into a movie, I delved back into some of the books.
However, the movie raked up old memories about the books in the press, and I got to read about the latent symbolism and the criticism heaped on them. The most interesting arguments concerned the The Problem of Susan.
It's like this, in the last book in the series, The Last Battle, all the children who had ever been to Narnia reassemble there, with the exception of Susan. In a flippant statement one child says "She is too interested now in nylons and lipstick and invitations to bother about Narnia.'
This statement became a handle for a lot of arguments about the denial of a sexual/feminine choices allowed to a woman. And among lots of literature devoted to the issue emerged this short story by Neil Gaiman - The Problem of Susan http://www.impalapublications.com/blog/index.php?/archives/2396-The-Problem-of-Susan,-by-Neil-Gaiman.html
The Last Battle also tells us that the entire Pevensie Family, with the exception of Susan was killed, and reassembled in Heaven (Narnia). It is implied that heaven was denied to Susan because of her silly indulgences. The short story deals with the problems faced by Susan and also questions a God who would punish a young girl so bitterly - leaving her an orphan on earth, for her preference for nylons/lipstick/invitations.
The whole argument is a riveting read, and loosens quite a few bolts and nuts in your head.