The Third Symposium on Numerical and Physical Aspects of Aerodynamic Flows, like its immediate predecessor, was organized with emphasis on the calculation of flows relevant to aircraft, ships, and missiles. Fifty-five papers and 20 brief communications were presented at the Symposium, which was held at the California State University at Long Beach from 21 to 24 January 1985. A panel discussion was chaired by A. M. O. Smith and includeq state ments by T. T. Huang, C. E. lobe, l. Nielsen, and C. K. Forester on priorities for future research. The first lecture in memory of Professor Keith Stewartson was delivered by J. T. Stuart and is reproduced in this volume together with a selection of the papers presented at the Symposium. In Volume II of this series, papers were selected so as to provide a clear indication of the range of procedures available to represent two-dimensional flows, their physical foundation, and their predictive ability. In this volume, the emphasis is on three-dimensional flows with a section of five papers concerned with unsteady flows and a section of seven papers on three dimensional flows: The papers deal mainly with calculation methods and encompass subsonic and transonic, attached and separated flows. The selec tion has been made so as to fulfill the same purpose for three-dimensional flows as did Volume II for two-dimensional flows.