Intro -- Preface -- Contents -- List of Contributors -- Proof-Theoretic Semantics: An Autobiographical Survey -- Grundlagen der Arithmetik, 17: Part 1. Frege's Anticipation of the Deduction Theorem∗ -- Frege's Class Theory and the Logic of Sets -- The Validity of Inference and Argument∗ -- Kolmogorov and the General Theory of Problems -- Disjunctive Syllogism without Ex falso -- The Logicality of Equality -- Eight Rules for Implication Elimination -- Focusing Gentzen's LK Proof System -- Intensional Harmony as Isomorphism -- A Note on Synonymy in Proof-Theoretic Semantics -- Paradoxes, Intuitionism, and Proof-Theoretic Semantics -- On the Structure of Proofs -- Truth-Value Constants in Multi-Valued Logics -- Counterfactual Assumptions and Counterfactual Implications -- Some Set-Theoretic Reduction Principles -- Comments on the Contributions -- Index.