A preliminary exploration of a potentially low-cost gas turbine thermodynamic cycle that appears capable of unprecedented efficiency. The cycle approximates an Ericsson cycle and uses stepwise expansions in turbines with intervening reheat and stepwise compression with intervening intercooling. At a peak cycle temperature of 1500 deg F, and using five stages of compression and expansion, a 50 percent thermal efficiency is attainable with previously demonstrated component performance. This performance requires no extremes of pressure or temperature, no new materials, and no fundamentally new techniques. The cycle is not complicated in comparison with advanced gas turbine/steam turbine cycles now being considered for high-efficiency fossil-fuel-fired plants. In addition, the low temperatures required by the Ericsson cycle would eliminate many problems presented by other cycles. This analysis indicates that detailed study of fuels and applications, design and plant layout, costs, and fuel processing losses for the Ericsson cycle approximation is warranted.