This book is the first part of a two-volume set that provides a foundation in operational gaming, the use of games to inform plans and sound decisions. It starts by discussing the ontogeny of games as they evolved with philosophy, theology, mathematics and computers, and goes on to evaluate games as a form of inquiry that can help accomplish individual and organizational aims. Special focus is placed on the role of games in addressing complex adaptive behaviors and measuring advances in artificial intelligence. The work includes primers on game theory for gamers, decision theorists, complexity scientists, and AI practitioners, and guidance to help them create game-oriented practice fields for decision-making and critical analysis.