This book brings research on taxonomy and natural kinds from the philosophy of science to bear on the science of perception. It defends a novel version of the property cluster view of natural kinds and uses it to explore many puzzling features of perception and cognition. It makes the case that natural kindhood is important for philosophers of perception, the methodology of psychology, and first-order issues in psychology itself. One of the book's central case studies is working memory. It contends that working memory is a natural kind, and that the natural kindhood of working memory can shed new light on the debate about the link between working memory and consciousness. Another core focus is consciousness in early life. The volume maintains that natural kinds are crucial for the question of when consciousness emerges in infancy. It uses the machinery of natural kinds to outline and defend a methodology for ascertaining when consciousness emerges in babies and infants. Finally, the book explores the link between natural kindhood and conceptual reform in psychology. It argues that psychological concepts that fail to refer to a natural kind ought to be eliminated from psychology.