This book constitutes the thoroughly refereed postproceedings of the 4th International Workshop on Programming Multi-Agent Systems, ProMAS 2006, held in Hakodate, Japan, in May 2006 as an associated event of AAMAS 2006, the 5th International Joint Conference on Autonomous Agents and Multiagent Systems.
The 12 revised full papers presented together with 2 invited articles are organized in topical sections on uncertainty of agents, lightweight devices for business and e-commerce applications, component-based agents for MAS simulation, dynamic logic programming in MAS, rule-based agents, affective agents and reinforcement agents, BDI agent frameworks, creation, execution, mobility and communication of agents, agent-like communication, validation, debugging and testing, multi-agent techniques and issues, multi-agent programming, as well as multi-agent platforms and organization.