From here on, monsters / Elizabeth Bryer.

"In a city locked in a kind of perpetual twilight, antiquarian bookseller Cameron Raybould accepts a very strange commission - the valuation of a rare codex. Within its fragile pages Cameron makes a curious discovery. Although seemingly ancient, the codex tells of a modern mystery: an academic missing for eleven years. Stranger still, as finding the truth becomes ever more of an obsession, Cameron begins to notice frightening lapses in memory. As if, all around, words, images, even people are beginning to fade from sight. As if unravelling the riddle of this book may be unravelling the nature of reality itself. And something frightening and unknown is taking its place..."--Publisher description.