The late Hector-Neri Castañeda, the Mahlon Powell Professor of Philosophy at Indiana University, and founding editor of Noûs, has deeply influenced current analytic pjilosophy with diverse contributions, including guise theory, the theory on indicators and quasi-indicators, and the proposition/practition theory. This volume collects 15 papers - for the most part previously unpublished - in ontology, philosophy of language, cognitive science and related areas by ex-students of Professor Castañeda, most of whom are now well-known researchers or even distinguished scholars. The authors share the conviction that Castañeda's work must continue to be explored and that his philosophical methodology must continue to be applied in an effort to further illuminate all the issues that he so deeply investigated. The topics covered by the contributions include intensional contexts, possible worlds, quasi-indicators, guise theory, property theory, Russell's substitutional theory of propositions, event theory, the adverbial theory of mental attitudes, existentialist ontology, and Plato's, Leibniz's, Kant's and Peirce's ontologies. An introduction by the editors relates all these themes to Castañeda's philosophical interests and methodology.