Presents the fundamental aspects of fusion welding for students, and serves as a handy reference for practicing engineers and research workers involved with the welding of engineering alloys. Deals with the metallurgy of welding, complementing existing welding handbooks and manuals, which tend to emphasize procedures for welding various materials. Examines the thermal, chemical, and mechanical aspects of welding; the metallurgical aspects of welding in three different regions of the weld--the fusion, the partially-melted, and the heat-affected zones--and the microstructure and properties of the weld. Outlines the difficulties in producing sound welds and practical approaches to overcome them. Also covers several important alloy systems and their representative heat-affected-zone phenomena. Includes numerous examples, problems, and case studies, and contains extensive references to the literature.