Advances in Modal Logic is a unique international forum for presenting the latest results and new directions of research in modal logic broadly conceived. The topics dealt with are of interdisciplinary interest and range from mathematical, computational, and philosophical problems to applications in knowledge representation and formal linguistics. This volume contains invited and contributed papers from the sixth conference in the series, held for the first time outside Europe, in Noosa, Queensland, Australia, in September 2006. It reports on considerable progress, both in the foundations of modal logic and in a number of application areas. It includes papers on the theory of modal logic itself, on process theory, multi-agent systems and spatial reasoning, and work on quantified modal logic, modal reasoning methods, and philosophical issues.