Specifically, that's the hollowed-out book Neo keeps his mini-discs of illegal software in. So the title is not just a reference to the movie's themes, it's also literally true: it's not a functional book, since it's hollowed out, it's a simulation of a book.

Interestingly, "Simulacra and Simulation" is not a title that was invented for the movie: http://www.amazon.com/dp/0472065211