If you liked the movie then you'll LOVE this book

Gangs of New York

This is an interesting history of gangs in New York City from the mid 1800's to I believe somewhere around the early 1920's. Talks about the many street battles and colorful characters, some of which seem to border on being folklore. These guys were legitimate hand to hand tough guys, not like the later weasely mafia types that would have somebody else shoot you in the back. These guys would fight it out themselves in the streets, in fact some of the guys talked about in this book were among the top bare knuckle boxers of their day and are featured prominently in a history of bare knuckle boxing book that I have.

A classic, ruined by the film

An account of the gangsters of NYC from the earliest days. There is some amazing untold history here. One which really struck me was the stories of the draft riots in NYC of the civil war. Apparently there was a $300 draft exemption whereby the well to do could get out of being turned into lunch meat in the civil war. It didn't go over well with the working class Irish in the city, who revolted (about 1/10 of the population was actively involved in the several days of riots) and made a huge mess of the place. Lots of interesting tidbits about river pirates, "the dead rabbit gang" (they marched under the banner of an impaled rabbit; "rabbit" incidentally, had numerous double entendres in those days which no longer exist), Monk Eastman, Dopey Benny, the Gopher gang, Bill the Butcher, Lupo the Wolf and other notorious gangsters from the beginning of NYC until the 1920s. This stuff makes the Mafia look like nice orderly guys.