Dragoslav D. Šiljak received his doctorate degree (D.Sc.) in Electrical Engineering from the University of Belgrade, Serbia, in 1963. He joined the Department of Electrical Engineering at the Santa Clara University in 1964, where he is presently the Benjamin and Mae Swig University Professor. Upon the arrival to Santa Clara, Dr. Šiljak continued his research on parameter space methods for robust control design, which he presented in a monograph Nonlinear Systems: The Parameter Analysis and Design (Wiley, 1969). He established collaboration with control groups at NASA Ames Research Center and Marshal Space Flight Center, which focused on parameter methods for control design of space vehicles. In the early 1970s, Dr. Šiljak introduced the concept of connective stability of large-scale dynamic systems within the framework of comparison principle and vector Lyapunov functions. He applied the concept to a wide variety of models, in areas as diverse as population biology, arms race, large space structures, competitive equilibrium in mathematical economics, and electric power systems. Within the same framework, he introduced robust decentralized feedback and developed graph-theoretic methods for decentralization and stabilization of uncertain large-scale systems. These concepts and results appeared in a monograph entitled Large-scale Dynamic Systems: Stability and Structure (North Holland, 1978) which, after almost thirty years, was reprinted as a paperback by Dover Publications (2007). In the 1980s, Dr. Šiljak and his collaborators developed a large number of new and highly original concepts and methods for the decentralized control of uncertain large-scale interconnected systems. Structurally fixed modes, multiple controllers for reliable stabilization, decentralized optimization, and hierarchical, epsilon, and overlapping decompositions laid the foundation for a powerful and efficient approach to a broad set of problems in control design of large complex systems. This development was reported in a comprehensive monograph Decentralized Control of Complex Systems (Academic Press, 1991). Over the past two decades, Dr. Šiljak and his collaborators have raised the research on complex systems to a higher level. Decomposition schemes involving inputs and outputs have been developed for and applied to complex systems of unprecedented dimensions. Dynamic graphs have been defined in a linear space as one parameter groups of transformations of the graph space into itself. This new mathematical entity opened the possibility to include continuous Boolean networks in a theoretical study of gene regulation and modeling of large-scale organic structures. These new and exciting developments have been published in a recent monograph Control of Complex Systems: Structural Constraints and Uncertainty (Springer, 2010, coauthor A. I. Zečević). Dr. Šiljak’s research on large complex systems has involved a large number of collaborators, including researchers and students who came from all over the world to Santa Clara to study complex dynamic systems. Over the years, this research has been generously supported by NASA, NSF, DOE, and DARPA. In 1981, Šiljak served as a Distinguished Scholar of the Japan Society for Promotion of Science, lecturing on large-scale systems at major universities and companies in Japan. He was selected as a Distinguished Professor of the Fulbright Foundation in 1984, and in 1985 became an Honorary Member of the Serbian Academy of Arts and Sciences. In 1986, he served as a Director of the NSF Workshop “Challenges to Control: A Collective View,” organizing a forum of top control scientists at Santa Clara University for the purpose of assessing the state of the art of the field and outline directions of research. In 1991, he gave a week-long seminar on decentralized control at the Seoul National University as a Hoam Distinguished Foreign Scholar. In 2001, he became a Life Fellow of the IEEE. He has presented many plenary talks at conferences and served on editorial boards of a variety of journals in the fields of applied mathematics and engineering.