This reference work is the second supplement to Dinosaurs: The Encyclopedia (a 1998 American Library Association Outstanding Reference Book) and follows the intent and format of the encyclopedia and first supplement. This continuation of what is now the standard encyclopedia provides up-to-date concepts and evidence of dinosaur paleobiology and evolution. Various competing positions are well presented and exhaustively referenced. The content is based on the latest original research of paleontologists, especially in dinosaur systematics, and genera, and covers such topics as the constant changes in technology and research methods, the Mesozoic Era in general, new theoretical ideas, the dinosaur-bird debate, dinosaur extinctions, and nomen nudum and excluded genera. Supplemental volumes do not repeat information from earlier volumes, but build upon them: view all volumes on the series page.