Melville C. Branch continues his lifelong examination of planning as inherent in all human activities, and the primary determinant of our prospects and survival as a species. This latest work discusses the use of simulation throughout society, as the representation of what is considered or planned. Simulation is everpresent in many different forms, such as financial statements representing the economic state of a business, flight simulators used in training pilots, and wind tunnels and hydrodynamic tanks employed in research. Scientific sample polls of relatively few people reveal the collective opinion of entire populations. Mathematical models are used to analyze all sorts of phenomena and to plan many activities. Literature, law, music, and art simulate human thoughts, emotions, concerns, and conclusions. Simulation is an essential element of individual behavior and societal action.