The philosophy underlying the development of SWAT teams is to provide a highly trained and disciplined team to act with efficiency to produce the successful termination of the hostage incident without casualties either to victims or offenders. Most SWAT teams have rigorous recruitment and training requirements. Training may cover physical conditioning, weapons use, controlling behavior under stress, and conducting hostage negotiations. In any hostage or barricade situation, the primary duty of the SWAT unit is to establish control of an inner perimeter. The uniformed patrol drops back to establish an outer perimeter. Because response time is a vital ingredient for dealing with hostage situations, members of SWAT teams generally carry enough gear in the trunks of their cars to respond to a call. Intelligence-gathering is initiated as the team takes over from the uniformed patrol. Problems facing SWAT teams include the handling of the media at the hostage scene and securing funding for equipment and training. With various forms of political terrorism on the rise both internationally and domestically, SWAT units are vital. The primary problem in establishing such units is gaining public acceptance of the concept and public support for funding. SWAT teams are not necessary for every city. Under mutual aid and assistance agreements, the service of such units can be obtained from neighboring metropolitan areas or, in the case of Federal violations, from the Federal Bureau of Investigation. A discussion of basic elements of tactical procedures is appended, and the practices of various metropolitan SWAT teams are described.