This volume provides English translations of texts that form the essential background to Kant's Critique of Pure Reason. Presenting the projects of Kant's predecessors and contemporaries in eighteenth-century Germany, it enables readers to understand the positions that Kant might have identified with 'pure reason', the criticisms of pure reason that had developed prior to Kant's, and alternative attempts at synthesizing empiricist elements within a rationalist framework. The volume contains chapters on Christian Wolff, Martin Knutzen, Alexander Baumgarten, Christian Crusius, Leonhard Euler, Johann Lambert, Marcus Herz, Johann Eberhard, and Johann Tetens. Each chapter includes a brief introduction that provides succinct biographical and bibliographical information on these authors, a concise account of their projects, and information on the importance of these projects to Kant's First Critique. Extensive references to the First Critique, brought together in a concordance, highlight the potential relevance of each text.