And "Homicide", written by David Simon while he shadowed Baltimore Homicide cops, and which served as the basis for several characters in the show.

https://www.amazon.com/Homicide-Killing-Streets-David-Simon/...

There was also the corner miniseries too!

http://www.imdb.com/title/tt0224853/

+1. The Corner is one of those books that literally changed my life. A must-read.