The detailed model for a criminal intelligence unit consists of the following subsystems: analysis and dissemination, source management, intelligence internal security, collections, and command and control. Functionally, intelligence units must be integrated into all aspects of the police organization, be systematically designed, use current social science research methods, and be responsive to a democratic society. Its tactics are explained and illustrated. A list of agencies possessing informative records and about 80 references are appended. Footnotes are included.