Not that I’m complaining! I love stories of people interacting with big institutions. It’s an odd and random literary taste, and very rarely satisfied in a non-meta way (I’m looking at you, Foster Wallace; I love you but that was really hard to read).
Basically, the idea is that the printing press was never invented. Instead, the Library of Alexandria has monopolized all the knowledge of the world and used it to gain political power. Sovereign states simply cannot exist without the Library.
As she explores the implications of this, Caine proves to have fully realized her world. The date is around 2030, but you only know that because a journal entry is dated early on. From the setting, it seems like it should be around 1850. The centralization and control of knowledge has badly retarded technological progress, and we see the process of stopping development in action as the novel unfolds.
The culture of the library itself, with it’s cutthroat policies, nepotism, and well-designed system, is at the dark heart of the novel. In this culture based around institutional inertia, a couple of kids try to get by, and get their hearts broken.