Currently on Radio 7, ht: Rosemary.
And written about by Pete Lowman: Chronicles of Heaven Unshackled: Part 2. Out of the Silent Planet
...this is basic to his fiction; in seeking to 'widen' his reader's notions of what the universe might possibly be conceived as including, he is aiming to make room for the Christian cosmology, along with much newly-imagined material. This is fiction with an apologetic purpose, even if it is much more than apologetics. The 'fictional hypothesis' is related to the author's worldview more directly than in Tolkien. As Lewis said of the second novel of the trilogy, Voyage to Venus, 'It wouldn't have been that particular story if I wasn't interested in those particular ideas on other grounds.