FUNDAMENTAL ASPECTS OF STRUCTURAL ALLOY DESIGN is the proceedings of the tenth Battelle Colloquium in the Materials Sciences, held in Seattle, Washington, and Harrison Hot Springs, B.C., September 15-19, 1975. The theme of the conference was the emerging science of alloy design. Although the relationships of properties of alloys to their composition and structure have long been a dominant theme in physical metallurgy, it is only recently that metallurgists have turned their attention from the analytical, post hoc study of the structure-property relationship to the synthesis approach of alloy design. As usual in the Battelle colloquia, the first day started with a group of introductory lectures presented by leaders in the field, each emphasizing his personal approach to the problem. This provided a historical perspective for the colloquium. These papers, together with the banquet address of Professor J. R. Low, Jr., who was honored at the colloquium, comprise the introductory section of these proceedings. Alloy design is generally specific to a given application. Thus, the needs in alloy design in a number of important applications, gas turbines, electrical-power-generation equipment, airframes, pressure vessels, and nuclear applications were presented in a group of papers. An agenda discussion on "Needs in Alloy Design" followed. These papers give the external constraints on alloy design applications, and criteria for mechanical, physical, and chemical properties for which the alloys must be designed.