Emphasizing the importance of understanding the past to make sense of the future, this book presents a historical analysis of the evolution of systematics during the last one hundred years. The authors examine the major issues that have driven the field and illuminate those that will be of importance in the immediate future. They present a general assessment of comparative biology's recent past, exploring the full impact of the cladistics revolution, a phenomenon that has yet to be fully appreciated, and provide a platform for further debate and discussion.