The book by Carlo McCormick and published by TASHEN is out in October and is highly recommended.
Here’s an excerpt from the introduction written by Banksy:
To some people breaking into property and painting might seem a little inconsiderate, but in reality the 30 square centimetres of your brain are trespassed upon every day by teams of marketing experts. Graffiti is a perfectly proportionate response to being sold unattainable goals by a society obsessed with status and infamy. Graffiti is the sight of an unregulated free market getting the kind of art it deserves.
Watch the first look at the publication: