The title is misleading - "the art and aesthetics of Hip Hop"... it barely touches on the 4 elements of Hip Hop (MCing, DJing, B-Boying, graffiti), and instead talks about 'Hip Hop' literature, theater, and other non-central aspects.
A book actually sticking to the title and breaking down the art and aesthetics of the 4 elements of Hip Hop would have been a great book - this book should have been called "some bits about b-boying and graffiti and then a lot of random things which I pulled out of a hat and are sort of related to Hip Hop" (though not the catchiest title, I agree).
Jeff Chang's intro made me laugh where he begins, "what you hold in your hands is not another book about rap music. This is about hip-hop".
This is funny on two levels - a) as I've just mentioned it doesn't cover the elements of Hip Hop solidly in the first place and b) it makes it sound like we're swamped with books on rap music.
I can count the number of books that actually properly focus on the music on a single hand - the majority of supposed Hip Hop books are academic dissertations on multiculturalism, race, politics, feminism, and so on... and this book seems to mostly be adding to that huge stack of not-particularly-Hip-Hoppy 'Hip Hop' books.
It's not so much that this is a terrible book, because there are some interesting parts, it's just that it needed a lot more focus to bring it in line with the awesome idea of the title. If you took maybe the interviews with the b-boys and graffiti guys, and then cut it down to just the bits dealing with their aesthetics, and then you added sections on DJing and MCing, and tied it all together, you'd have a book that did what it says on the front.
As it is, the different contributors are simply left to wander through their own spheres, mostly rambling, and most Hip Hop fans will be wondering when they can actually read about something that seems relevant.