Although many private security personnel perform functions similar to public law enforcement officers, they generally have no more formal authority than an average citizen. Basically, the security officer authority is derived directly from the entity they are hired to protect and indirectly from various sources of law. Tort law, which regulates civil relationships between people, is the primary source for security personnel's authority. Tort law sets limits on the activity of security personnel by defining, through case precedent, the boundaries of reasonable conduct. Like tort law, criminal law acts only as a deterrent to improper conduct and defines conduct parameters for security officers. Under contract law, the business enterprise could create standards of conduct for agency guards more restrictive than those permitted by law. Similarly, the U.S. Constitution sets forth the basic rights of all individuals; in doing so, it places limitations on the conduct of the Government and its officers. Security officers who have been commissioned by a Government agency are thus restricted further as to authority. Finally, the private security business is frequently regulated by State and local statutes, ordinances, rules, and regulations, all of which may be termed administrative law. These laws are concerned with the qualification, hiring, and training of security personnel. They generally do not confer special authority on the security personnel licensed under such provisions. The article provides 21 footnotes.