The advantages of a liquid-coupled indirect-transfer-type gas-turbine-plant regenerator relative to the conventional direct-transfer-type are described. The indirect system consists of two units, one a hot-gas-to-coupling-liquid exchanger, and the other a coupling-liquid-to-compressed-air heater, together with the necessary circulation system for the coupling-liquid. One of the liquid metal alloys possessing a high heat-transfer coefficient, a low freezing point, and a high boiling point might prove to be suitable as a coupling liquid. As an example, the sodium-potassium eutectic alloy might be practical. Design studies are presented to give an idea of the geometry of indirect-type regenerators for four different gas-turbine cycles. One of these cycles may be considered as typical of a conventional open-cycle central station or marine plant; the second is like the first only it is a closed-supercharged cycle; the third is a locomotive plant, and the fourth is an aircraft turboprop system. The principal conclusion reached is that, granting the successful development of a suitable coupling liquid, the indirect-type regenerator possesses so many advantages over the direct type that it may prove to be a strong competitor.