Who is Professor Weston from Perelandra and what is their importance?

Professor Weston is the vehicle through which the Un-Man is able to fight Ransom in a human form. He is unable to gain victory over Ransom, in the same way that Satan was not victorious over Christ. He and Ransom first meet on Mars, and he later comes to Perelandra in search of the spiritual, which he claims is the whole mission of man. Weston claims to have acheived to an enlightened spiritual level, but he is prideful, and is it is his pride that opens the door to the Un-Man overtaking his body and soul.