A review of the history and present scope of law enforcement in America introduces the field and identifies personnel needs and future developments. Opportunities at the city and county level are then discussed, including applicant personal requirements, physical examinations, written tests, interviews, and the selection process. The career progression is outlined from probation and tenure to promotion. Specific job descriptions deal with the patrol officer, the traffic officer, the detective, the female police officer, and the county units. Opportunities at the State level consist of State police and highway patrol, civilian positions, and regulatory units. Military and Federal opportunities are described in terms of the Federal agencies and typical job assignments. Information on salaries is presented for Federal employment, along with comments on fringe benefits, other incentives, frustrations, and the element of danger inherent in police work. Educational requirements for high school, college, and cadet programs involving a work-study approach are given. Recruit training and the Law Enforcement Education Program providing grants are also described in this context. In conclusion, reference is made to careers in related fields, such as corrections, criminal justice and law, private security and loss prevention, criminalistics and the crime lab, polygraph operation, document examination, and lab technology. National associations and Federal agencies are listed. A recommended reading list and a list of selected colleges with criminal justice curricula are appended.