An overview of police work in the United States notes that the most important function of the police officer is law enforcement that results in the collection of evidence, the apprehension and prosecution of criminals, the maintenance of order, and the protection of the public. In addition to the role of the police in America, this paper addresses control over the police, the diversity and multiplicity of law enforcement agencies, the selection and training of law enforcement personnel, political influences on the police, police corruption and deviance, and dealing with many of the problems that affect law enforcement in the United States. The function of the prosecutor in the United States is primarily to represent the people by prosecuting those who are alleged to have committed crimes. Issues discussed are becoming a prosecutor, working as a prosecutor, the charging decisions, the grand jury, the preliminary hearing, checks on prosecutorial discretion, and plea bargaining. The focus of the section on police-prosecutor relations is their mutual dependence in ensuring that criminals are convicted, problems in the relationship, and the resolution of conflicts between police and prosecutors in the course of developing a strong case.