I have no hesitancy about 'rushing in where angels fear to tread', nor for that matter 'putting my foot in my mouth', therefore:
That ole boy, I call him Jack, was born about the same time as my sainted father: ca 1898. He grew up an atheist, but he got over that when he was about 30. Meanwhile he was a great scholar and fellow at Oxford, but little appreciated.
Around 42 he was invited to write on Christianity for the BBC. His lectures made him famous.
He had embraced strict orthodoxy, as most of his theological works attest, but like his friend Tolkien, he sort of wandered a bit in the field of fiction.
The space trilogy makes good reading, but it was other stuff that really grabbed me: the Narnia series, the Great Divorce, and finally Till We have Faces.
By my outlandish evaluation Jack drifted perilously away from strict orthodoxy in his mythopoeic works. In the Last Battle one image (near or at the end) really gripped me:
The children were ascending a mountain ledge to the goal of "Farther in and Higher up". They look across a chasm and see another ledge, and on that ledge they see their parents, far away from them, but they see that the two ledges are converging at the top.
Wonderful! Magnificent! There is more than one path to God.
The Great Divorce is a mini masterpiece: a fair reader can get through in half an hour (you can even find the first chapter on the net).
It was said to be an answer to Blakes Marriage of Heaven and Hell, but I see it in a far different light.
Even people who didn't make the good place are allowed a holiday up there occasionally (if they're interested). (I must say that setup largely formed my concept of heaven.)
The only people not up there have simply refused to go- or stay; they had other interests. They live in a sort of shadowy suburb where the lots get bigger and bigger (curious about Napoleon one observer tracked him down and found him something like 60 million miles away from his nearest neighbor).
Anyone may stay in heaven if he's willing, but he can't keep any souvenirs from hell. In this mythopoeic work I hear Jack saying that hell is reserved for those who refuse heaven, and the door remains open. That's a long way from the strict orthodoxy he had emphatically embraced 16 years before. Of course he made no claim that it was anything other than a dream.
Till We Have Faces, his last fictional work, is reserved for the connoisseurs of C.S.Lewis. I won't even attempt to abstract it here.
Lewis may have been the most influential writer on religion in the 20th century.