I never heard of C.S. Lewis growing up (he also wrote science fiction Christian books, such as the Narnia Chronicles, Perlandra, A Grief Observed and Mere Christianity, the best easy summation of Christianity I've ever come across). My first encounter was when I was taking a seminary course that met at St. Thomas, a very HIgh English church in NY. I asked who he was as people discussed him. Hoots of you don't know? followed. I told myself to ignore them b/c they lived very closed lives.
I moved on to confirmation classes. Satan was given very short shift. Demons terrorized me in the Witnesses. I was so afraid I would turn on all lights and search behind every door hinge and shower curtain (and closets, too). Of course, I no longer had rational belief but terrified I was. I was embarassed to reveal the extent of it to my confirmation teacher. After explaining that I was raised a fundamentalist, I said fear of Satan remained a problem. He said do not fear. God has already solved the problem. They are not equals. He promised me if I read C.S. Lewis, The Screwtape Letters, my mind would change. As soon as physically possible, I obtained the book. It is a series of letters from Screwtape, a supervisor devil, to his younger nephew in the field, Wormwood. Lewis is confident that the Devil has no chance and to focus extensively on Our Father is to be silly. He mocks Satan and does it well.
The letters are entertaining. No Watchtower rhetoric here. Lewis reveals how the devils can use true problems in the church that are so identifiable such as parish shopping, contempt for a neighbor's lousy singing, etc. Many times I saw my own reaction to church. He is not preachy. The mirth of the letters is sustained through the entire book. The very names for the devils are hilarious, Globuse, Triptweeze. The book is so effective that many all night lights were extinguished.
Lewis' true masterpiece is Mere Christianity, a summation of essential Christian beliefs that almost all churches have - sans WTBTS. The Screwtape Letters and Mere Christianity were written during the height of World War II. Since Britain has no Establishment Clause, they started as BBC broadcasts to encourage resistance to the Germans. My life would truly be dreary and not as rich without these books.
His children's books that are really adult books are wonderful. While I am recommending books, let me plug A Wrinkle in Time by Madeleine L'Engle, which has been banned in some places. I never heard of her, either. She is hot in Christian circles. I met her when I was near death's door. She spent many hours talking with me and supporting me. Without Madeleine and a volunteer at St. John the Divine in NY, I'd be dead. In fact, I was much too ill to read her masterpiece for a long while. These books are profound and joyous. Would anyone categorize the WT that way? Perhaps I savor them so much because of the WTBTS.