- In the book of Genesis, God tells the serpent "I will put enmity between you and the woman, and between your offspring and hers; he will crush your head, and you will strike his heel." The serpent is commonly thought to be Satan. In Perelandra, the Un-Man (a representative of Satan) bites Ransom's heel, and Ransom crushes the Un-Man's head with a rock. Very clever, Mr. Lewis.
- In the book of Revelation, Jesus promises that the one who overcomes will inherit the morning star, which is another name for Venus (Perelandra in The Space Trilogy.) In Second Corinthians, Paul mentions someone who was caught up into the third heaven, which could also correspond to Perelandra.
- The Un-Man's clear desire in Perelandra to shut off its mind whenever it's not actively using its intelligence to seduce the Green Lady makes even more sense when you recall some passages in A Preface To Paradise Lost where Lewis discusses how one of the things the Fallen most hate is to be reminded of what they once had. That portion of the Devil inhabiting Weston's body is in an unfallen world. Everything around it, every bird and beast and tree and blade of grass, is a reminder of the Heaven that the Devil lost by its own actions. No wonder it has no wish to think about the world around it.
- Similarly, this lends new significance to its habit of attacking the flora and fauna of Perelandra. Not only is it giving vent to its malice, but it is also trying to blot out the message that it so desperately wishes not to receive.
Fridge / The Space Trilogy