For anyone who owns an iPad, I recommend this iBook about graffiti: Henry Chalfant’s Graffiti Archive. It archives NYC train graffiti in the 1980s - the formation of Hip Hop! If you are into art, street lore, sociology or even if you just like the pictures, this book is awesome. See here:
https://itunes.apple.com/us/book/hen...31594319?mt=11