Comprising the past 600 million years of earth history, the Phanerozoic is the era when plant and animal life as we know it developed. Although many processes of evolution and ecology cannot be studied directly in the fossil record, the results of such processes often can be. Here twenty-one leading paleontologists use important refinements in fossil diversity data to provide critical evaluations of older hypotheses of diversification and extinction processes and to propose fresh interpretations. They treat major patterns of diversity, the modeling of diversity patterns and diversity change, community-level contributions to diversity patterns, and diversity effects within taxonomic groups. Contributors include William I. Ausich, Richard K. Bambach, David J. Bottjer, Timothy R. Carr, W. A. Clemens, Karl W. Flessa, Margaret C. Hardy, Michael L. Hulver, David Jablonski, Jennifer A. Kitchell, Andrew H. Knoll, Arnold I. Miller, Kark J. Niklas, K. Padian, J. John Sepkoshi, Jr., Philip W. Signor III, Bruce H. Tiffney, Richard H. Thomas, James W. Valentine, Timothy Dane Walker, and Peter D. Ward.