Now, Out of the Silent Planet - that's a title to conjure with. Good story too, as it turns out - I reviewed it a while back. But Perelandra? A bit nondescript in comparison, IMHO. Although, admittedly better than Voyage to Venus, as which it was briefly published.
The science - now we've actually managed to get to Venus - is even more wrong than it was in Silent Planet. But, since no-one knew that 60 years ago, we'll let that go. Lewis has the planet permanently shrouded in cloud, and since that much is accurate, I'm willing to suspend my disbelief for the duration of the story.
A story which is (although the author points out that none of the human characters are allegorical) a thinly veiled allegory for the fall of man in the Garden of Eden, with the result that there is less depth to the story than there was to Silent Planet.
None of which, thankfully, prevents it being a good story - if only a good re-telling of the Eden story.
Here, the voice of evil is not represented by anything as innocent as a snake. Oh no, it's Professor Weston - the bad guy from the first volume of the trilogy, gone badder. At times he is just a human with some very bad thoughts, but for most of the story he is seen as the subject of a demonic possession. Indeed, the existence of 'demons' and their interest in the outcome of the story is present in the introductory chapters, in which Lewis, as narrator, goes to meet Ransom.
It is Ransom's task to provide a counter argument to Weston's attempts to subvert the paradise of Venus. In his attempts to do so, we not only encounter the varied landscapes of Perelandra, but also witness some fairly bloody scraps between the two men.
The whole adventure is almost like Narnia with all the nasty bits left in: the evil Weston is utterly evil, but not in the exaggerated way some fantasy can portray evil; he retains just enough humanity to make him all the more disturbing. Likewise Ransom, the good guy, is flawed, doubting his own ability to fulfil his mission, and so the initially simple premise is developed into something much more.
On the downside, at times the story is hijacked by the main characters philosophising - which is OK for fans of C.S. Lewis, because he does it so well, but kind of messes up the action if you're not interested in the reason behind the action (in which case you probably picked up the wrong book to start with anyway).
Ultimately, good wins out, as it is obliged to do, and this version of the Eden story ends without the fall of Perelandrian man. So apparently, one man can make a difference.