Police violence that is clearly illegal should be distinguished from violence that is simply the unnecessary result of police incompetence. Awarding large amounts of compensation to victims of unlawful violence who sue the police and dispelling citizens' unrealistic expectations of the police are two potentially effective but unlikely means of reducing extralegal violence by police. However, this violence is probably much less common than police violence resulting from simple incompetence. A variety of situations contain the potential for violence, but changes in the ways that police handle them could reduce the incidence violence. Police should use two principles: tactical knowledge and concealment. Tactical knowledge involves gathering prior information about the setting and people involved. Concealment means using physical cover or disguising one's intent or identity until the moment of least hazard. Using concealment would both minimize the risks to officers, bystanders, and suspects and prevent tragic mistakes. Thus, police officers should learn from fire services and the military, both of which spend considerable time diagnosing and planning for contingencies that they may face. Analyses that follow violent situations should also focus less on the outcomes than on whether officers respond in ways likely to reduce the potential for violence. Footnotes and 15 references. ABI cfw