For each of six topics -- use of force; complaints and misconduct investigations; promoting accountability and effective management; training; non-discriminatory policing and data collection; and recruitment, hiring, and retention -- the booklet presents principles for police behavior and instruction under varying circumstances. Regarding the use of force, principles address both deadly and non-deadly force, as well as the continuum of force. Principles for the use of force also focus on the use of canines to apprehend suspects, administrative review of shootings and the use of deadly force, use-of-force reporting, and the administrative review of the use of non-deadly force. Principles that pertain to complaints and misconduct investigations cover accepting misconduct complaints, reports of misconduct, misconduct investigations, and the resolution of misconduct investigations. Principles for promoting accountability and effective management encompass information management systems ("early warning" systems), supervision, searches and seizures, public information and feedback, and meaningful civilian input. Principles for traffic stops, the conduct of law enforcement stops, data collection, and persons with limited English proficiency are delineated under the general topic of nondiscriminatory policing and data collection. In addition to principles for recruitment and hiring, the concluding section presents principles for assignment and promotion as well as the prevention of harassment. Appended examples of promising police practices and policies and 48 annotated listings of U.S. Department of Justice research, resources, and programs on police practices.