Introduction Editor's Introduction i Feature Articles Improving Privacy in Vickrey Auctions Natalia López, Manuel Núñez, Ismael Rodríguez, and Fernando Rubio 1 A Multi-party Contract Model Lai Xu 13 Convergence, Steady State, and Global Gains of Agent-based Coalition Formation in E-markets Kwang Mong Sim, Yuanshi Wang, and Hong Wu 24 Experiments with Planning and Markets in Multiagent Systems Naveenkumar Muguda, Peter R. Wurman, and R. Michael Young 34 Conference Reports Conference Report: The Fifth ACM Conference on Electronic Commerce David M. Pennock 48 ISSN 1551-9031