Simulations help people understand large, complex problems using smaller, simpler models. This book delves into the history and thinking behind simulations. Readers will learn about Georg Leopold von Reiswitz's development of a Kriegsspiel for military training, and other major developments. This volume also gives examples of ways that simulations can be useful, and discusses data sources. A concluding simple simulation will round out the learning experience, and encourage readers to create their own simulation. Sidebars and photographs accompany the text to aid readers in their exploration of simulations.