The main focus of this book is about smart materials and their applications in smart structures. Smart materials are the products of new emerging science and technology. The advent of smart materials has revolutionized their use in numerous infrastructural system and are also picking up at an unprecedented pace. Smartness describes self-adaptability, self-sensing memory and multiple functionalities of the materials or structures. In this book the importance of smart structures, strain measurement and the various sensing technologies that can be implemented in the structures has been discussed. The smart materials and structures find their way into aircraft, trains, civil engineering structures and domestic appliances.