In this book an introduction to the strengthening of reinforced concrete (RC), concrete and steel members using externally bonded steel plate or fiber reinforced polymer (FRP) composites sheets and plates by reviewing the most significant investigations reported in the literature. In addition, a section is devoted to the strengthening of RC members in shear utilizing FRP plates and sheets. However, since the external plating and its application as a strengthening technique has only been made possible by the development of suitable adhesives, consideration is also given to the types of adhesive which may be used for external plate bonding and their requirements for this application. After considering reported plate bonding studies, a brief review of surface preparation techniques applicable to FRP and concrete adherents is presented.