Interfaces control the properties of many technologically important materials. For many years, however, alloys have primarily been designed with the focus on optimizing bulk properties. Recently, much more attention has been paid to designing interfaces to improve the performance of materials. This idea has been central in the development of nanoscale devices in the electronics industry, but now these concepts have also been applied to both grain boundaries and phase boundaries in structural materials. There has been a breakthrough in the area of advanced experimental tools, such as the analysis of electron backscattering patterns and in the improved simulation capabilities of interfaces in complex engineering alloys. Third has been the recognition that failures often are associated with interfaces and that materials can be processed to improve the properties. This book concentrates on the preparation and processing of interfaces, the relationships between chemistry and structure and the properties and behavior of interfaces, particularly in relation to strength and bonding. Topics include: general concepts and modeling; reactions and wetting; interface structure/composition/character; mechanical properties and abstracts of other invited papers