The chapter begins with a historical review of policing in the United States. There is discussion of the various types and levels of law enforcement agencies from federal law enforcement agencies to special-purpose and private police. Then, the discussion turns to the command structure of police departments. This is followed by an examination of police functions and issues relating to police and community. Next, the chapter focuses on the rule of law in law enforcement, deficiencies in its application, and methods to correct those deficiencies. Finally, there is discussion of police subculture, reasons for its existence and the negative impact it can have on police officers and their families.