This chapter reviews the chemical, physical, and mechanical characteristics of nickel-based superalloys, emphasizing their use in turbine engines. It discusses the role of alloying additions in multicomponent commercial cast and wrought superalloys, microstructural stability, and processing methods. The chapter also covers the mechanical properties and deformation mechanisms, including tensile properties, creep, fatigue, and cyclic crack growth. Superalloys are highlighted for their exceptional high-temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments, making them widely used in aircraft and power-generation turbines. The text details the processing routes for cast and wrought superalloys, including investment casting, directional solidification, and wrought processing, and addresses the challenges and advancements in each method. Additionally, it explores the microstructural evolution and the impact of alloying elements on the properties of superalloys, such as the formation of γ' precipitates and the role of impurities. The chapter concludes with a discussion on the mechanical properties of superalloys, including their creep resistance, and the challenges in predicting these properties due to the complex microstructure.This chapter reviews the chemical, physical, and mechanical characteristics of nickel-based superalloys, emphasizing their use in turbine engines. It discusses the role of alloying additions in multicomponent commercial cast and wrought superalloys, microstructural stability, and processing methods. The chapter also covers the mechanical properties and deformation mechanisms, including tensile properties, creep, fatigue, and cyclic crack growth. Superalloys are highlighted for their exceptional high-temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments, making them widely used in aircraft and power-generation turbines. The text details the processing routes for cast and wrought superalloys, including investment casting, directional solidification, and wrought processing, and addresses the challenges and advancements in each method. Additionally, it explores the microstructural evolution and the impact of alloying elements on the properties of superalloys, such as the formation of γ' precipitates and the role of impurities. The chapter concludes with a discussion on the mechanical properties of superalloys, including their creep resistance, and the challenges in predicting these properties due to the complex microstructure.