Franz Brentano (1838-1917) led an intellectual revolution that sought to revitalize German-language philosophy and to reverse its post-Kantian direction. His philosophy laid the groundwork for philosophy of science as it came to fruition in the Vienna Circle, and for phenomenology in the work of such figures as his student Edmund Husserl. This volume brings together newly commissioned chapters on his important work in theory of intentionality, theory of judgment, the reform of syllogistic logic, empirical descriptive psychology and phenomenology, theory of knowledge, metaphysics and ontology, value theory, and natural theology. It also offers a critical evaluation of Brentano's significance in his historical context, and of his impact on contemporary philosophy in both the analytic and the continental traditions.