commenter:
If I could recommend a pair of his books, it would be “That Hideous Strength” and “The Abolition of Man”.
Excellent picks, but I suggest reading the other two books of that trilogy first: Out of the Silent Planet and Perelandra.
The Geeat Divorce is wonderful as well… in fact, everything I’ve ever read by him is top-shelf.
OH, OH! - Till We Have Faces!! Read that too!
Heck, just get everything he ever wrote.