Cladistics is the method of choice for systematic classification and comparative studies in all fields of biology. In cladistics, reconstructed genealogies are based on common ancestry rather than on simple anatomical similarity and therefore effectively reveal true phylogenetic relationships. This book is an introduction to cladistics and is based on the popular training course originally offered by the Systematics Association. The book first introduces the principle of parsimony and methods for character coding and the determination of character polarity. Methods of cladistic tree-building follow and tree statistics are detailed. Alternatives to parsimony, molecular applications of cladistics, and the relevance of fossils are then discussed. The concluding chapters review two important topics in cladistics: cladistic biogeography and the implementation of cladistic results in systematics. This book provides an up-to-date account of the techniques of modern cladistics, written in a clear, readable style. It will be an invaluable text for all students interested in systematics and comparative studies.