How do radically new kinds of organisms evolve? The Origin of Higher Taxa addresses this essential question, specifically whether the emergence of higher taxa such as orders, classes, and phyla are the result of normal Darwinian evolution acting over a sufficiently long period of time, or whether unusual genetic events and particular environmental and ecological circumstances are also involved. Until very recently, the combination of an incomplete fossil record and a limited understanding about how raw mutations lead via modified ontogenic processes to significant phenotypic changes, effectively stymied scientific debate. However, it is now timely to revisit the question in the light of the discovery of considerable new fossil material (and new techniques for studying it), together with significant advances in our understanding of phenotypic development at the molecular level.This novel text incorporates evidence from morphology, palaeobiology, developmental biology, and ecology, to review those parts of the fossil record that illustrate something of the pattern of acquisition of derived characters in lineages leading to actual higher taxa as well as the environmental conditions under which they occurred. The author's original ideas are set within the context of a broad and balanced review of the latest research in the field. The result is a book which provides a concise, authoritative, and accessible overview of this fascinating subject for both students and researchers in evolutionary biology and palaeontology.