**About the Editor**

**Ronald W. Armstrong** (Professor Emeritus) obtained a Bachelor of Engineering Science (BES) degree from the Johns Hopkins University in 1955 and a Doctor of Philosophy (PhD) degree in metallurgical engineering from Carnegie Institute of Technology, now within Carnegie-Mellon University, in 1958. A post-doctoral year was spent at the Houldsworth School of Applied Science, Leeds University, UK, in 1958–9, followed by a Westinghouse Research Laboratory appointment in 1959–64, and then at the Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Tribophysics, University of Melbourne, Australia, in 1964. His academic positions were at Brown University, 1965–68, and the University of Maryland, College Park, 1968–1999. From 2000–2003, he was a senior scientist at the Munitions Directorate, Eglin Air Force Base, FL. Temporary positions have been with the US Office of Naval Research, London, UK, in 1982–84 and 1991, as a liaison scientist, and at other US government and overseas university and government laboratories. His research experience has mainly dealt with the dislocation mechanics of plasticity and fracturing in polycrystalline materials.
