The Mysterious Flame of Queen Loana.
By Umberto Eco.

I've just started the novel. Like Silverlock (thanks, Randy), it's one of those books that contain a kind of map to a bajillion others. Unlike Silverlock, there probably won't be a happy ending. Some kind of tragedy will cap it off; it's Umberto Eco.

In the Eco-ian universe, books aren't merely stand-alone islands to be traversed in linear fashion; they are nodes in an exponentially expanding extranet. To read one book, you sometimes have to pass through several others, accumulating countless references and subtexts along the way. "We've been reading books in a hypertextual way ever since Homer," Eco says. "We read a page and then we jump, especially when we're rereading it. Think of the Bible. When people read it, they're always jumping here and there, constantly connecting various quotations."
-- Village Voice article.

Further quote:

Eco says he structured Mysterious Flame to mimic the free-associative behavior of electronic navigation. (Indeed, his latest nonfiction book to be published stateside, The History of Beauty, was originally conceived as a CD-ROM.) But Eco stops short when asked about the all too real physical convergence of books and online matter. "I'm very skeptical about that," he says. "The real function of a novel is to give the reader the impression that destiny can't be altered. With electronic material, you can change it whenever you want. But a novel tells you that life can't be changed. That's its power."

Link to a wiki-style annotation site added to the toolbar, so I don't forget where I put it.