This book contains a selection of papers presented at the International Seminar ''Negotiation and Market Engineering'', held at Dagstuhl Castle, Germany, in November 2006.The 17 revised full papers presented in this volume were carefully selected and reviewed after the seminar. The papers deal with the complexity of negotiations, auctions, and markets as economic, social, and IT systems. The authors give a broad overview on the major issues to be addressed and the methodologies used to approach them, covering highly interdisciplinary research from computer science, economics, business administration, and mathematics.