A brief account is given of the historical evolution of giant pulse lasers and of the level of performance of such lasers that has so far been achieved. Those aspects of the interaction of light with a plasma that are of importance in plasma heating are briefly reviewed, and a detailed treatment including the results of computer calculations is given of the heating of a spark within a homogeneous gas, the subsonic heating of an isolated gas sphere, and the pressure resulting from light-induced blow-off.It is concluded that existing giant pulse lasers have sufficient brightness to be potentially capable of producing plasmas with kilovolt temperatures and tens of megabar pressures, but that a major increase in output power will be required before this potential can be realized. The design of future giant pulse lasers that are particularly well suited to the achievement of extremely high output power at high brightness is discussed.