Mobile video systems may be one of the bigger assets in police work. Because of its versatility, video has become one of the better modern courtroom tools, and is especially valuable in DWI cases. Video can also be used: (1) to corroborate the testimony of witnessing officers by showing the consistency in their stories; (2) as evidence for officers accused of brutality or excessive force, allowing internal affairs investigators to check the validity of a complaint without tying up the officer's and investigator's time with paperwork; (3) as the only accurate witness, since it is not subject to the vagaries of recall, interpretation or perception of human witnesses; and (4) as a valuable training tool. Perhaps the only negative aspect of mobile video systems is that officers typically resist them at first, complaining that they don't want Big Brother peering over their shoulder and critiquing their every move. But after using a camera for awhile, most officers quickly realize that it can protect them more often than it will ever be used to hurt them. The article includes information on system requirements, legal criteria, and source list for mobile video systems.