Demand-side management (DSM) is the planning and implementation of those electric utility activities designed to influence customer uses of electricity in ways that will produce desired changes in the utility's load shape. While the objective of any DSM activity is to produce a load-shape change, the art of successful implementation and the ultimate success of the program rests within the balancing of utility and customer needs. This paper describes demand-side management for electric utilities and discusses the evolution of this concept for load management, strategic conservation, and marketing.