This article examines the foundations of gaming and related concepts, such as policy exercises and serious gaming, in a public policy making context. Examining the relevant publications in "Simulation & Gaming" since 1969, the author looks back at the development of gaming simulation for purposes such as public policy analysis and planning, and reviews the underlying theories and empirical evidence. The author highlights the recognition that the success of gaming for policy making derives largely from the unique power of that gaming to capture and integrate both the technical-physical and the social-political complexities of policy problems. (Contains 13 notes, 1 table, and 4 figures.)