The workshop on Declarative Agent Languages and Technologies is a we- established venue for researchers interested in sharing their experiences in the areas of declarative and formal aspects of agents and multi-agent systems, and in engineering and technology. Today it is still a challenge to develop techno- gies that can satisfy the requirements of complex agent systems. The design and development of multi-agent systems still calls for models and technologies that ensure predictability, enable feature discovery, allow for the veri?cation of properties, and guarantee ?exibility. Declarative...

This book constitutes the thoroughly refereed post-proceedings of the 4th International Workshop on Declarative Agent Languages and Technologies, DALT 2006, held in Japan in May 2006. This was an associated event of AAMAS 2006, the main international conference on autonomous agents and multi-agent systems. The 12 revised full papers presented together with one invited talk and three invited papers were carefully selected for inclusion in the book.