Modal logic is one of the most widely applied logical formalisms. Systems ofmodal logic are being used in many disciplines, ranging from artificialintelligence, computer science, mathematics, formal grammar and semantics tophilosophy. This volume presents substantial recent advances in the relationaland the algorithmic treatment of modal logics. It contains papers from thefifth conference on "Advances in Modal logic," held in Manchester (UK) inSeptember 2004. Written by leading experts in the field, the present book isindispensable for any advanced student and researcher in pure and applied modallogic.