A security guard (or security officer) is a person who is paid to protect property, assets, or people. Security guards are usually privately and formally employed personnel. Often, security officers are uniformed and act to protect property by maintaining a high visibility presence to deter illegal and inappropriate actions, observing (either directly, through patrols, or by watching alarm systems or video cameras) for signs of crime, fire or disorder; then taking action and reporting any incidents to their client and emergency services as appropriate

'One massive resource, filled with significant numbers of personnel, armed with a wide array of technology, and directed by professionals who have spent their entire adult lifetimes learning how to prevent and reduce crime, has not been tapped by governments in the fight against criminality. The private security industry, with over one million workers, sophisticated alarm systems and perimeter safeguards, armored trucks, sophisticated mini-computers, and thousands of highly skilled crime prevention experts, offers a potential for coping with crime that can not be equalled by any other remedy or approach.... Underutilized by police, all but ignored by prosecutors and the judiciary, and unknown to corrections officials, the private security professional may be the only person in this society who has the knowledge to effectively prevent crime