As computer science enters the new millennium, methods and languages for reasoning with constraints have come to play an important role, with both t- oretical advances and practical applications. Constraints have emerged as the basis of a representational and computational paradigm that draws from many disciplinesandcanbebroughttobearonmanyproblemdomains, includingar- ?cial intelligence, databases, and combinatorial optimization. The conference is concerned with all aspects of computing with constraints including algorithms, applications, environments, languages, models and systems. The Sixth...