A Drink Before the War by Dennis Lehane
I didn't enjoy this novel as much as Shutter Island or Mystic River, but it's his first novel, so obviously he was still developing. Having said that, it was still entertaining and much more developed and thoughtful than other murder mystery series. I mean how many other detective series really have any attempt at racial analysis? I'm not saying he comes to any conclusions or draws the proper ones, but the narrator actually questions his actions at the end and asks himself if he behaved differently towards two people based on their race.
He acknowledges the beliefs of those around him that he in fact occasionally echoes without trying to make himself look better or justify himself. As far as the actual story, Patrick, the narrator, and his partner Angie are private investigators in Boston, and are hired to find a cleaning woman who has disappeared with certain documents. Of course there is a lot more to it than that, and the two quickly finds themselves involved in political intrigues and a gang war. With the gang war, some of the action towards the end of the novel got a little over the top for my tastes, but mostly it was an intelligently written mystery, which is impressive since so many of them tend to be fluff.