Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Twenty Years Serving The N.Y.P.D.

This excellent read chronicles the authors career in the NYPD between 1961 and 1981. He writes about his days from a naive rookie to his time on the Tactical Patrol Force and Narcotics enforcement, till he testifies before the Knapp Commission. He offers valuable insight to the culture of graft that permeated not only much of the N.Y. Police Department but the also much of the legal and political system at the time. Interesting as well are his observations on the young Rudy Giuliani.