Harry L. Van Trees, ScD, is University Professor Emeritus at George Mason University. His career spans a variety of academic, government, and industry positions. He spent fourteen years as professor of electrical engineering at Massachusetts Institute of Technology. During this period he developed the three-volume series, Detection, Estimation, and Modulation Theory, which are the classical texts in the area and still widely used throughout the world. At George Mason University, he completed Part IV of the DEMT series, Optimum Array Processing. He served as chief scientist of the U.S. Air Force, principal deputy assistant secretary of defense for C3I, president of M/A-Com-Linkabit Government Systems, and founding director of the C3I Center at George Mason University. He is currently engaged in academic research at George Mason University, and is a consultant to several companies and government agencies. Kristine L. Bell, PhD, is Associate Professor in the Department of Statistics and C3I Center at George Mason University. In her doctoral thesis, she developed a significant generalization of the Ziv-Zakai bound that expanded its range of applicability. Her current research interests are in the areas of robust, adaptive signal processing techniques and performance bounds for source location and tracking with applications in radar, sonar, aeroacoustics, and satellite communications.