Stephen J. Zaccaro, Ph.D., is a professor of psychology at George Mason University, Fairfax, Virginia and President of Zaccaro Leadership Systems, LLC. He is also an experienced leadership development consultant. He received his Ph,D. in social psychology from the University of Connecticut. He has been studying, teaching, and consulting about leadership and teams for over 40 years. He has written over 150 journal articles, book chapters, and technical reports on leadership, group dynamics, and team performance. He has authored a book titled, The Nature of Executive Leadership: A Conceptual and Empirical Analysis of Success, and has co-edited six other books on the topics of organizational agility, organizational leadership, leader development, multiteam systems, cyber-security, and occupational stress. He has worked with executives and managers from private industry as well as from the educational, nonprofit, government, and military sectors. He serves on the editorial boards of The Leadership Quarterly, Advances in Global Leadership, Journal of Leadership and Organizational Studies, and Journal of Character and Leadership Development. He is also an associate editor for the Journal of Business and Psychology. He is a Fellow of the Association for Psychological Science, and of the American Psychological Association, Divisions 14 (Society for Industrial and Organizational Psychology) and 19 (Military Psychology). He is also the current president of the Interdisciplinary Network for Group Research (INGRoup).