The book uses STELLA software to develop simulation models, allowing readers to convert their understanding of a phenomenon into a computer model and run it to yield the inevitable dynamic consequences built into the structure. Part I provides an introduction to modeling dynamic systems, while Part II offers general modeling methods. Parts III through VIII apply these methods to model real-world phenomena from chemistry, genetics, ecology, economics, and engineering. It serves as a clear, approachable introduction to the modeling process, relevant in any field where real problems can be illuminated by computer simulation.