Wolfgang Spohn, born 1950, is one of the most distinguished analytic philosophers and philosophers of science of Germany, editor-in-chief of Erkenntnis for more than 13 years, author of two books and more than 60 papers covering a wide range: epistemology, metaphysics, and philosophy of science, philosophical logic, philosophy of language and mind, and the theory of practical rationality. This collection presents 15 of his most important essays on theoretical philosophy. The centre piece is his 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 the papers included. They cover an account of deterministic and also probabilistic causation, initially subjectively relativized, but then objectivized in a projectivistic sense, and an account of explanation and of strict, of ceteris paribus, and of chance laws. They advance a coherentist epistemology, though giving foundationalist intuitions their due, and establish some coherence principles as a priori true, entailing even a weak principle of causality. They finally shed light on concept formation by more broadly embedding the epistemological considerations into the framework of two-dimensional semantics. All this is carried out with formal rigor when feasible.