Presenting a historical analysis of the evolution of systematics during the last one hundred years, this book reviews many of the major issues in systematic theory and practice that have driven the working methods of systematics during the 20th century and looks at the issues most likely to preoccupy systematists in the immediate future. The authors stress the importance of understanding the past to make sense of the future. They present a general assessment of comparative biology's recent past and how it has matured and blossomed. Exploring the full impact of the cladistics revolution, a phenomenon that has yet to be fully appreciated, the book provides a platform for further debate and discussion.