It's also worth watching the film "Exit through the giftshop" on Netflix. Goes over Banksy in decent depth, as well as some other famous street artists.
That was such a fascinating movie. Hopefully not spoiling much of it, but the way the subject of the documentary seesaws from Banksy to "the director" and back was really interesting.
I'm not sure what to believe by the end of that documentary, but it sure was a wild ride.
I think that was the best part; the debate among friends at the end as to what we actually just watched