Electric utility least-cost planning is formulated in terms of supply- and demand-side options, irreducible uncertainties, and stakeholders' objectives. Planning methods include constrained optimization, tradeoff analysis, and game theory. Constrained optimization is the traditional and still most popular approach. Tradeoff analysis, which seeks good compromises, seems most appropriate for today's least-cost planning environment. It is suggested that game theory, which is particularly useful in a competitive and noncooperative environment, may play a role in least-cost planning. >