From the Amazon.com review:
For one thing, people there each have a personal dæmon, the manifestation of their soul in animal form. For another, hers is a universe in which science, theology, and magic are closely allied:Anyone with a rudimentary understanding of Christianity knows that comunicating with demons is, how you say, "frowned upon"? Pulman is either an occultist, or he is being used by the demonic.As for what experimental theology was, Lyra had no more idea than the urchins. She had formed the notion that it was concerned with magic, with the movements of the stars and planets, with tiny particles of matter, but that was guesswork, really. Probably the stars had dæmons just as humans did, and experimental theology involved talking to them.
In either case, stay the hell away.
Pullman’s use of daemon is not the classic Christian meaning of demon. He’s trying to be cute here. He detaches a person’s soul from the person and makes it into another being, an animal, although they really are attached because if one dies, so does the other. Then he calls this animal form of soul a “daemon.” He’s definitely making a statement. I have no respect for Pullman at all. He’s a skillful writer, though.
OMG, I remember reading a science fiction novel ca 1971 that had something of this concept in it. Remember little of it now.