With increasing frequency, systematic and evolutionary biologists have turned to the techniques of molecular biology to complement their traditional morphological and anatomical approaches to questions of the historical relationship and descent among groups of animals and plants. In particular, the comparative analysis of DNA sequences is becoming a common and important focus of research attention today. The objective of this volume is to survey the emerging field of molecular systematics of DNA sequences, and to appraise the strengths and limitations of the different approaches yielded by the