The purpose of the American Society for Testing and Materials Conference on Composite Materials: Testing and Design was to provide a forum for the discussion of analytical and experimental studies of advanced composites. Emphasis was on the development of a basic understanding of the mechanical and structural behavior of both organic and metal matrix composites. The program brought together for the first time, comprehensive, detailed, and significant work in the areas of mechanical properties testing, as well as examples of design application. The ultimate aim of the society, speakers, and participants was uniformly the same one; to pave the way for quicker and more widespread utilization of the use of composite materials in military and commercial aircraft, missiles, and space vehicles, and naval and other structural component applications. In recent years advanced composite materials reinforced with high-strength, high-modulus filaments have received increasing attention. This activity has been motivated by the potential for superior performance in structural and other applications afforded by the unique capabilities of such composite materials. The very nature of these advanced composites, namely, the heterogeneity and the high stiffness and strengths, however, has been introducing new problems in both testing and in the development of appropriate design procedures. Thus, innovations in testing techniques and design philosophy have been needed urgently. A short range goal of the sponsoring ASTM Subcommittee on Composites, D-30, has been to derive ideas for new test methods and design and analysis procedures from the technological fallout of this conference. The technical papers which were presented at the conference and which are included in this volume were divided into four sessions and were in some cases given in simultaneous presentations over a period of three days. The four sessions were entitled “Testing, Fatigue and Creep, Design and Application, and Fracture Mechanics,” and each session was opened with a keynote address by an outstanding expert in his field. Although questions and answers were not recorded and published, a lively question and answer period followed each paper.