As an introduction to the subject of gasdynamic lasers, I would like to discuss briefly some of the fundamental limitations on the average power output of laser devices. The most fundamental limitation on the average power output of a laser is the removal of waste energy resulting from the inefficiency of a laser. This waste energy may appear in the form of excited metastable states or simply as heat. In Figure 1 an analysis of various methods for removal of this waste energy are examined. Most laser devices, whether solid or gas, have an active medium of the form of a long, thin cylinder. With no flow or very little flow waste energy is removed by diffusion to the outer surface of the cylinder. In the case of a solid it is simply heat conduction to the wall where it is removed by a coolant; in the case of a gas laser, it is diffusion of metastable states or heat to the outer walls of a cylindrical container.