This book constitutes the refereed proceedings of the 4th International Conference on E-Commerce 2003, held in Prague, Czech Republic in September 2003.

The 42 revised full papers presented together with an invited paper and a position paper were carefully reviewed and selected from 108 submissions. The papers are organized in topical sections on auctions, security, agents and search, ebXML, modeling and technology, XML, design and performance, business processes, and brokering and recommender systems.

We welcome you to the Second International Conference on E commerce and Web Technology (ECWEB 2001) held in conjunction with DEXA 2001 in Munich, Germany. This conference, now in its second year, is a forum to bring together researchers from academia and commercial developers from industry to discuss the state of the art in E commerce and web technology and explore new ideas. We thank you all for coming to Munich to participate and debate the new emerging advances in this area. The research presentation and discussion during the conference will help to exchange new ideas among the...