Inquiry, argumentation and knowledge -- Rational control of reasoning in artificial intelligence -- Computational issues in belief revision -- Some results on theory revision -- Epistemic entrenchment with incomparabilities and relational belief revision -- The negative Ramsey test: Another triviality result -- A nonmonotonic conditional logic for belief revision -- Relations between the logic of theory change and nonmonotonic logic -- Belief revision in a framework for default reasoning -- Preferential cumulative reasoning and nonmonotonic semantic nets -- Propositional logic based on the dynamics of disbelief -- On the modal logic of theory change -- Discourse representation theory and belief dynamics -- Multiple contraction a further case against gärdenfors' principle of recovery.

The logic of theory change, or the theory of belief revision, is a growing area of research in artificial intelligence. The papers in this volume, mostly arising from a workshop held in Konstanz in October 1989, chart out the current state of research in this area and indicate the directions of future research. Connections to other areas of AI research are emphasized throughout the book. All the contributions are original research papers and most of them are self-contained, so that the collection will be of interest not only to researchers but also to all those who seek an introduction to the state of the art in this area. The fourteen contributions are organized into five sections: - Foundations - Models of theory change - The Ramsey test for conditionals - Theory change and nonmonotonic reasoning - Reformulations and extensions.