Grimm and Railsback start with a primer on modeling: how to design models that are as simple as possible while still solving specific problems. Next, they address the problems of theory and conceptual framework for individual-based ecology: What is “theory”? How do we develop reusable models of how system dynamics arise from individuals? What conceptual framework do we use when differential equations no longer apply? An extensive review illustrates the variety of ecological problems already addressed with individual-based models. The authors then address how the mechanics of individual-based modeling differ from those of traditional science and provide extensive guidance on formulating, programming, and analyzing models. This book will be helpful to any ecologist interested in modeling, and to any scientist interested in agent-based modeling.