Vienna, Warsaw, Copenhagen.- The Cracow Circle.- Austrian Origins of Logical Positivism.- The Approach to Metaphysics in the Lvov-Warsaw School.- Ajdukiewicz's Contribution to the Realism/Idealism Debate.- Towards Universal Grammars Carnap's and Ajdukiewicz' Contributions.- Principles of Categorial Grammar in the Light of Current Formalisms.- On 'Categorial Grammar'.- Meta-Ethics: Contributions from Vienna and Warsaw.- The Project to Create an Empirical Ethical Theory.- Mereology and Metaphysics: From Boethius of Dacia to Lesniewski.- Definitions in Russell, in the Vienna Circle and in the Lvov-Warsaw School.- ?ukasiewicz, Meinong, and Many-Valued Logic.- ?ukasiewiczian Logic of Tenses and The Problem of Determinism.- Kasimir Twardowski: An Essay on The Borderlines of Ontology, Psychology and Logic.- Some Remarks on the Place of Logical Empiricism in 20th Century Philosophy.- De Veritate: Austro-Polish Contributions to the Theory of Truth from Brentano to Tarski.- The Lvov-Warsaw School and the Vienna Circle.