This work addresses the current need for a holistic approach in comparative and evolutionary biology and offers numerous applications of the modern methods of phylogenetic systematics and historical ecology, using the North American fish fauna as its case study. This major synthesis, the first published work of its kind, provides a theoretical and methodological foundation for future studies in ichthyology, evolutionary biology, or other fields of comparative biology. Several introductory pieces present major statements of general principles, detailed examinations of the diversity and distributions of North American freshwater fishes, and what is known of their systematic relationships. The rest of the volume’s 30 papers then contribute new phylogenetic hypotheses for a significant number of taxa.