Magnesium and magnesium alloys provide unique properties for engineering applications. Magnesium alloys are popular as a structural material because of their combination of light weight and strength. They are desirable for portable tools, appliances, electronic devices, airplanes, space vehicles, and land transportation. This book is written for engineers, scientists, teachers, and students engaged in the design process of material selection and material elimination. While focused on mechanical properties for structural design, the physical properties that are germane to corrosion behavior and electrical applications are represented. Two-thirds of the book is devoted to datasheets for individual alloys which provide a handy quick reference to specific properties and performance. The remainder of the book addresses topics common to all magnesium alloys such as the alloy designation system and product forms. Casting alloys and wrought alloys are compared. The alloy performance at elevated temperature is presented, as are fatigue properties. Finally, a summary of the corrosion behavior of selected alloys is discussed along with how these corrosion mechanisms can be applied for beneficial results.