Andrew Cooper presents the first systematic study of Kant's account of natural history. Cooper contends that Kant made a decisive contribution to one of the most explosive and understudied revolutions in the history of science: the addition of time to the frame in which explanations are required, sought, and justified in natural science. Through addressing a wide range of Kant's works, Cooper challenges the claim that Kant's theory of science denies a developmental conception of nature and argues instead that it establishes a method by which natural historians can genuinely dispute historical claims and potentially come to consensus. This method, Cooper argues, can be used to expose serious flaws in Kant's own historical reasoning, including the formation and defence of his racist views. The book will be valuable to philosophers seeking to discern both the power and limitations of Kant's theory of science, and to historians of science working on the fractured landscape of eighteenth-century Newtonianism.