Superalloys are nickel, iron-nickel, and cobalt-base alloys generally used for high-temperature applications. Superalloys are used in aircraft, industrial, marine gas turbines, nuclear reactors, spacecraft structures, petrochemical production, orthopedic and dental prostheses, and environmental protection applications. This Article discusses the material characteristics, phases, structures, and systems of superalloys. It describes the processing of superalloys, including primary and secondary melting, deformation processing (conversion), powder processing, investment casting, and joining methods. The Article also describes the properties, microstructure, and thermal exposure of superalloys. It further discusses the effects of environmental factors on superalloys, including oxidation and hot corrosion. Protective coatings are also discussed. The Article provides information on the mechanical properties and chemical composition of nickel, iron, and cobalt-base superalloys in both the cast and wrought forms.