Developed for use by the aerospace industry and for military aircraft, carbon fibers are now employed where low density, highest specific strength, and stiffness are required. They are generally employed as composites, with a matrix of epoxy, polyester, or polyimide resin. Their outstanding fatigue resistance, chemical inertness, and high temperature resistance have been the impetus for much research. Chemistry of preparation, structure, surface properties, mechanical properties, and applications are reviewed. -- AATA