Currently, there are three techniques used for delivery of whole-body hyperthermia. The simplest of these is direct contact between skin and some surrounding fluid. The surrounding fluid can be either water, wax, air, or other fluid medium; heat is transferred from the surrounding fluid to the body surface. Vessels in the skin surface transfer heat to the perfusing blood, which uniformly distributes it throughout the body. The second technique uses irradiation of the body surface with nonionizing radiation to deliver heat to the first few cm from the surface. This heat can be picked up by local blood perfusion and distributed throughout the body. One advantage of this method over direct contact methods is that heat is deposited throughout the first few cm and therefore temperature increases at the surface are lower. The third technique is extracorporeal perfusion which seems the most promising method for delivery of whole-body hyperthermia. This allows for greater control of central temperature via rapid change in temperature of blood passing through the external heat exchanger. The increased ability to control temperature resulting from this advanced instrumentation allows accurate delivery of whole-body hyperthermia. This permits comparison studies of therapeutic effectiveness.