- Cult Classic: The books are certainly not as well known as Lewis' other works, but have received just as much praise from those who have read them.
- Hilarious in Hindsight:
- The Unman talking about the "Force" as an energy which comes from all life and commands his actions, a full thirty-plus years before Star Wars.
- While Ransom tries to deduce which planet he's on in Out of the Silent Planet, he concludes that it isn't Venus, because he thought Venus would be a bit hotter. This was written in 1938, almost twenty-five years before the surface temperature of Venus was measured and found to be ludicrously hotter than Earth's rather than just "a bit".
- Nightmare Fuel:
- The battle with the Unman and the Crapsack World speech by Weston in Perelandra.
- Also in Perelandra the underground section can be incredibly creepy. Not just because most of it takes place in total darkness, but because there are lots of hints that all sorts of bizarre persons and places exist down there and the reader only sees enough of them to hint at it. And what little we see is hinted to be not necessarily ''evil'' but so ''foreign'' to human experience that it's incomprehensible.
- The detailed description of the head and the creepy paintings in That Hideous Strength. Also Dr. Frost's POV segments.
- Older Than They Think: That Hideous Strength (and ideologically, all three books) addresses the issue of transhumanism and many of its implications. Its first printing was in 1945.
- Stealth Pun: The oblivious figurehead of the villainous N.I.C.E. is Horace Jules, a clear parody of H. G. Wells. Now, not only does his last name recall his contemporary SF author, Jules Verne, but if you pronounce "H. Jules" aloud, it sounds a fair bit like "H. Gee-wells."
- "Seinfeld" Is Unfunny: At the time the trilogy was first published, most aliens in SF stories were hostile savages intent on destroying humanity. For Lewis's aliens to be morally superior to man was a radical departure... which was widely adopted by later writers, somewhat diluting its impact today. Though the thing that remains the most original with Lewis' premise is that his aliens still believe in a deity (one who is implied to be the same one who led the Hebrews out of Egypt at that), while most other sci-fi examples don't.
- Values Dissonance: The long discussions about gender roles in That Hideous Strength, as several of the protagonists try to convince the feminist Jane Studdock that a woman's place is to submit to her husband, can seem very odd to modern-day readers, especially those who don't share Lewis's traditionalist views on the subject.
- Except this is Jane's reaction to what she and Mark are both supposed to learn (and finally do) - that you can't love someone on your own terms. While Jane confronts her fear of being treated instrumentally, the distrust and distance towards others this begets, Mark slowly comes to understand that he has been hurting people in precisely this manner, that he could have hurt Jane in precisely this manner and that he has no ownership over Jane, nor any title to said ownership. He thinks this outright on the last pages on the novel, on his way to meet Jane again.
- Values Resonance: When listing examples of all that is base and ignoble in the British spirit, Dimble mentions famous imperialist Cecil Rhodes in the same breath as Oliver Cromwell and Mordred. At the time, Rhodes was often celebrated as a visionary businessman, but today he is more likely to be condemned for his virulent racism and cruel exploitation of the places he subjected to British control.
- What Do You Mean It Wasnt Made On Drugs: Perelandra can get rather trippy at times...
YMMV / The Space Trilogy