Immanuel Kant’s work changed the course of modern philosophy; in these essays Karl Ameriks examines how. He compares the philosophical system set out in Kant’s Critiques with the work of the major philosophers before and after him (Descartes, Berkeley, Hume, Reid, Jacobi, Reinhold, the early German Romantics, Hegel, Feuerbach, and Marx). A systematic introduction argues that complexities in the interpretation of Kant’s system led to a new emphasis on history, subjectivity, and aesthetics. This emphasis defined a distinctive interpretive style of philosophizing that has become especially influential and fruitful once again in our own time. The individual essays provide case studies in support of the thesis that late 18th-century reactions to Kant initiated an ‘historical turn’, after which historical and systematic considerations became joined in a way that fundamentally distinguishes philosophy from science and art, without falling back into mere historicism. In this way it is shown that philosophy’s ‘historical turn’ is both similar to and unlike the turn to history undertaken by most other disciplines in this era. Part One argues that close attention to the historical context of Kant’s philosophy is crucial to avoiding frequent misunderstandings that have arisen in comparing Kant with other major modern philosophers. Part Two contends that it was mainly the writing of Kant’s first major interpreter that led to special philosophical emphasis on history in other major post-Kantian thinkers. Part Three argues that Hegel’s system and its influence on post-Hegelians were determined largely by variations on Reinhold’s historical turn. Part Four engages with major contemporary philosophers who have combined a study of particular themes in Kant and German Idealism with an appreciation for phenomena closely associated with the general notion of an historical turn in philosophy.