A shape-memory alloy (SMA) refers to a type of alloy that deforms when cold but returns to its pre-deformation shape on being heated. The parts made from SMA are lightweight and solid-state alternatives for traditional actuators, such as motor, and hydraulic and pneumatic based systems. They are also useful for creating hermetic joints in metal tubing. The two most common SMAs are nickel-titanium (NiTi) and copper-aluminium-nickel. SMAs can also be made by alloying copper, iron, zinc and gold. SMAs exhibit varying shape-memory effects and the two most prevalent effects are one-way SMA and two-way SMA. The SMAs can be created through casting in which vacuum arc melting or induction melting is used. They have applications in various areas such as orthopedic surgery, aircraft and spacecraft, robotics, smartphone cameras, valves, optometry, medicine, and dentistry. This book presents the researches that have transformed the understanding of the properties and applications of shape-memory alloys. It is appropriate for students seeking detailed information in this area of metallurgy as well as for experts.