This book provides a definition of aerospace materials as structural components that bear the stresses imposed on the airframe throughout flight operations, encompassing taxiing, take-off, cruising, and landing. Safety-critical airframe components of aircraft, including the empennage, wings, fuselage, and landing gear; helicopter fuselage, tail boom, and rotor blades; and spacecraft airframe, coverings, and thermal insulation tiles, including the space shuttle, all comprise structural materials. Additionally, aerospace materials include the structural components of jet engines that support the forces required to generate thrust and propel the aircraft. Because they are critical to the performance and safety of aircraft, the materials utilized in the primary components of jet engines, including the turbine blades, are classified as structural materials within this book. Aerospace engineering has served as the driving force behind the advancement of sophisticated engineering materials. The development of sophisticated materials is contingent on their strength, rigidity, resistance to damage, density, as well as corrosion resistance at both ambient and elevated temperatures. Currently, life cycle costing is acknowledged as a method for determining the material’s economic viability, with the exception of aerospace engineering. The quantity of fuel consumed is directly influenced by the reduced take-off weight of a aircraft, space vehicle, or satellite; lightweight construction yields enormous economic and ecological benefits.