The papers collected in this volume, most of them derived from presentations at the Amsterdam Seminar on Intensional Logic, report recent work in pure and applied intensional logic, and are written by researchers from philosophical and mathematical logic, artificial intelligence and computational linguistics. Most of the contributions deal with modal or temporal logic, either as a topic or as a tool. Another major theme in the book may be described as 'representing changing information'. The papers constitute an important collection, addressing issues that have received a good deal of attention in recent years. The volume is aimed at researchers and students in logic, both pure and applied, and artificial intelligence. It is also of interest to philosophers and computational linguists.