That's because it's not a book on AI at all [0]. It talks about it a lot. And sets up a lot of fundamental ideas for it. But it's as much a book about AI as Moby Dick is a book about whaling.
It's great reading if you're interested in AI (edit: If you're on HN, you'll probably love the book /edit), but if you pick it up expecting an AI textbook, or a book about AI, you may be disappointed. Or at the very least, won't get the full message.
Another book I'd recommend is "The Minds I" by Douglas Hofstadter and Daniel C. Dennett. It's a collection of essays about AI and philosophy, relating to the idea of the "self", with several pages of reflection after each essay by Hofstadter and Dennett. I'm about halfway through so far, but it was worth it alone just for chapter 5, "The Turing Test: A Coffeehouse Conversation". Also the Ant Fugue from GEB is one of the featured essays.
[0] Though you can't really fault anyone for believing that. Hofstadter complains in the intro of the 20th anniversary edition (and several interviews) that everyone thinks the point of GEB is something different. And it's never what he intended the point of GEB to be.
Specifically, he says "GEB is a very personal attempt to say how it is that animate beings can come out of inanimate matter. What is a self, and how can a self come out of stuff that is as selfless as a stone or a puddle?"