This book collects 15 of the most important essays on theoretical philosophy by Wolfgang Spohn. Born 1950, he is one of the most distinguished analytic philosophers and philosophers of science in Germany and has published on a wide range of subjects: epistemology, metaphysics, and philosophy of science, philosophical logic, philosophy of language and mind, and the theory of practical rationality. The book offers valuable insights on the nature of causation, laws, coherence, and concepts. The centre piece is Spohn's uniquely successful theory of the dynamics of belief, tantamount to an account of induction and nowadays widely acknowledged as 'ranking theory'. Like any account of induction, this theory has deep implications ingeniously elaborated in all the papers included in this volume.