Abstract: A cooled turbine blade (either a rotor blade or a stationary vane) comprises a blade structural member whose primary function is to withstand the various loads exerted on the blade and maintain structural integrity of the blade, and a heat-transfer sheath that surrounds the outer surface of the structural member. A plurality of coolant passages are formed between the structural member and the heat-transfer sheath. Thus, when coolant is passed through the coolant passages, the heat transferred to the sheath from the hot gases passing through the turbine is in turn transferred to the coolant, which is then removed from the blade, thereby cooling the blade.