Study data came from 13 selected county and municipal police departments from several areas of the Nation. Secondary employment is an accepted practice in all the police departments. Some departments permit private employers to rent police vehicles and other police services as well. The departments have similar rules and practices concerning secondary employment, but each department has evolved its own method of organizing and managing this employment. The major difference among departments is whether their organization conforms to an officer contract or a department contract system of secondary employment. The departments all forbid officers from owning a private security firm or brokering the employment of fellow officers. Policy and management issues involved in secondary employment include legal liability, conflict of interest, misconduct and misuse of authority, the handling of complaints, and off-duty court attendance. Public police have an advantage over private police in both their greater formal authority and their greater informal powers. The officer contract system requires less organization and administration than does the department contract system. However, municipalities with 100,000 or more residents seem to be shifting toward the department contract system, which appears to be a more rational way to allocate staff when private demand for police service exceeds the supply. 178 notes.