The present volume has its origin in a meeting of philosophers,
linguists and cognitive scientists that was held at Umea University,
Sweden, September 24-26, 1993. The meeting was organized by the
Department of Philosophy in cooperation with the Department of
Linguistics, and it was called UmLLI-93, the Umea Colloquium on Dynamic
Approaches in Logic, Language and Information. The papers published here
are considerably expanded and revised versions of talks presented by
invited speakers at this colloquium. The papers included here fall into
three broad categories. In the first part of the book, Action, we have
collected papers that concern the formal theory of action, the logic of
nonns, and the theory of rational decision. The papers in the second
part, Belief Change, concern the theory of belief dynamics in the
tradition of Alchourr6n, Gardenfors and Makinson. The third part,
Cognition, concerns abstract questions about knowledge and truth as
well'as more concrete questions about the usefuleness and tractability
of various graphic representations of infonnation. An additional and
important topic of the colloquium concerned logical approaches to
natural language. For the sake of the thematic unity of this book, and
its appearance in the series Trends in logic, the colloquium papers
related to language are not included here, but some of these
contributions will appear in the philosophical journal Theoria.