The Third Conference in Inverse Design Concepts and Optimization in Engineering Sciences (ICIDES-III) will be held in Washington, D.C., October 23-25, 1991. This Conference will bring together a diverse international group of researchers to report on worldwide activities and to discuss technical issues in parallel sessions. The major areas are: aerodynamics, heat transfer, structural mechanics, interdisciplinary problems in materials processing. The Conference is jointly supported by the National Science Foundation, NASA, Office of Naval Research, and the Pennsylvania State University.