Don J. Torrieri is an author, Electrical Engineer, and Mathematician. His primary research interests are communication systems, adaptive arrays, and signal processing. He is a Fellow of the US Army Research Laboratory, where he was employed for most of his career. He has authored many articles and several books including "Principles of Spread-Spectrum Communication Systems, 4th edition" (Springer, 2018). He has taught many graduate courses at Johns Hopkins University, Baltimore, Maryland and many short courses. Don Torrieri received the B.S. degree from the Massachusetts Institute of Technology, Cambridge, the MS. degree from the Polytechnic Institute of New York University, Farmingdale, and the Ph.D. degree in electrophysics from the University of Maryland, College Park. His most important and most cited paper is "Statistical Theory of Passive Location Systems," IEEE Transactions on Aerospace and Electronic Systems. According to Google Scholar, this paper has been cited more than 1,650 times as of 2020. His most important and most cited book is "Principles of Spread-Spectrum Communication Systems”, 4th edition. According to Google Scholar, this book has been cited more than 460 times as of 2020.