Neutral models are constructed to help scientists understand complex patterns of form, structure, or behavior that may not be observed directly. In this unique volume, eight distinguished scientists present a comprehensive study of the use of neutral models in testing biological theories. They describe the principles of model testing and explore how they are applied to research in molecular biology, genetics, ecology, evolution, and paleontology. In addition to the editors, the contributors include Stephen Stigler, David Raup, Paul Harvey, L.B. Slobodkin, Stuart Kauffman, William Wimsatt, and James Crow.