This story is a WONDERFUL sequel to Out of the Silent Planet. Both Ransom and Lewis have evolved as characters.
With that said, this story takes a WILD twist and turn. There will be entire chapters dedicated to debate of Philosophy and Theology. Lewis does an excellent job of making you care about the characters and situation to care about the conversations being had.
Further, with a spoiler warning given, I will say there is an amazingly WILD conversation Ransom has with himself where he must decide whether or not to Box a devil, Cambridge style. For that scene alone, this book is worth listening to or reading.
I've never been curious about the Space trilogy before now, but it is essential Lewis and absolutely deserves a read or listen.