A major transformation in research and training is expected, using new, more advanced versions of computer-based systems. Technology now affords new capabilities: complex and distributed expert decisionmaking and team performance can now be elicited and rehearsed through affordable and easily distributed systems. These new systems will transform research and training on two fronts. It will allow research needed to bridge the gap between internal (i.e. laboratory control) and external (e.g. operational relevance) validity. In addition, it enables a coalition of forces, from training instructors and their students, to research scientists and quantitative performance modelers. While simulation-based research and training is rapidly advancing, with increased funding and sponsorship, as yet there is no comprehensive documentation of tools and techniques. This book addresses the problem, bringing together experts from a variety of perspectives. Their contributions document emerging trends and issues with regard to development, utilization, and validation of these emerging 'scaled world' systems. The readership includes researchers and practitioners who develop and/or utilize simulation-based environments, educators interested in instructional technology and researchers who require criterion-based performance evaluation.