Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
Third-Person Limited Omniscient and Third-Person Omniscient
Throughout Possession, the narrative voice shifts as the situation demands. The narrator often focuses on telling us things about one character at a time, and the narrator will often use free-indirect speech while he or she is at it. What's that, you ask? It just means that the narrator's voice is often tinged with the perspectives of the characters being described. For instance:
There had been, she remembered, his special airtight specimen box, glass-lined and sealed. She found it where it was kept; he was orderly in his habits. It would be ideal for her purpose.
There was a decision to be made and tomorrow would be too late. (25.37-38)
In this passage, the narrator starts out in a relatively straightforward third-person, limited-omniscient voice. We're told what Ellen Ash remembered and did, and we get the third-person pronoun "she."
Then, the narrative voice makes a subtle shift into free-indirect speech. The narrator doesn't say "She knew it would be ideal for her purpose" or "She knew that tomorrow would be too late": instead, the narrator simply states Ellen Ash's perceptions as if they were facts. In moments like these, Possession's narrative voice does something like a Vulcan mind meld with the brains of the characters.
There are other moments throughout Possession when we encounter a more wholeheartedly omniscient narrator who obviously knows all there is to know about each of the characters. This voice appears in passages where we learn things about the novel's nineteenth-century characters that none of its twentieth-century people will ever get to know. This narrative style also comes gets used in passages where the narrator takes a step back from the narrative to speak to us directly. Check out this passage, for example:
And yet, natures such as Roland's are at their most alert and heady when reading is violently yet steadily alive. (What an amazing word 'heady' is, en passant, suggesting both acute sensuous alertness and its opposite, the pleasure of the brain as opposed to the viscera—though each is implicated in the other, as we know very well, with both, when they are working.) (26.39)
In the long passage from which we've taken this short example, our narrator not only takes a step back from the narrative to present us with a short manifesto on the pleasures of reading, but also takes another step back from that manifesto to share a few thoughts about the specific choice of words here. This isn't just an omniscient narrator at work—it's an omniscient narrator who's self-reflexive about his or her own storytelling abilities.
Well played, A. S. Byatt. Well played.