Understanding the history and philosophy of biological systematics (phylogenetics, taxonomy and classification of living things) is key to successful practice of the discipline. In this thoroughly revised Third Edition of the classic Biological Systematics, Andrew V. Z. Brower and Randall T. Schuh provide an updated account of cladistic principles and techniques, emphasizing their empirical and epistemological clarity. Brower and Schuh cover: -the history and philosophy of systematics -the mechanics and methods of character analysis, phylogenetic inference, and evaluation of results -the practical application of systematic results to: -biological classification -adaptation and coevolution -biodiversity,and conservation -new chapters on species and molecular clocks Biological Systematics is both a textbook for students studying systematic biology and a desk reference for practicing systematists. Part explication of concepts and methods, part exploration of the underlying epistemology of systematics, This third edition addresses why some methods are more empirically sound than others.