The design of intelligent trading agents, mechanisms, and systems has received growing atttention in the agents and multiagent systems communities in an e?ort to address the increasing costs of search, transaction, and coordination which follows from the increasing number of Internet-enabled distibuted el- tronic markets. Furthermore, new technologies and supporting business models areresultinginagrowingvolumeofopenandhorizontallyintegratedmarketsfor trading of an increasingly diverse set of goods and services. However, growth of technologies for such markets requires innovative solutions to a diverseset of - isting and novel technical problems which we are only beginning to understand. Speci?cally, distributed markets present not only traditional economic pr- lems but also introduce novel and challenging computational issues that are not represented in the classic economic solution concepts. Novel to agent-mediated electronic commerce are considerations involving the computation substrates of the agents and the electronic institutions that supports trading, and also the human agentinterface (involving issues of preference elicitation, representation, reasoning, and trust). In sum, agent-mediated electronic trade requires prin- pled design (from economics and game theory) and incorporates novel combi- tions of theories from di?erent disciplines such as computer science, operations research, arti?cial intelligence, and distributed systems. The collection of above-mentioned issues and challenges has crystallized into a new, consolidated agent research ?eld that has become a focus of attention in recent years: agent-mediated electronic commerce."

The design of intelligent trading agents, mechanisms, and systems has received growingattentionin the agentsandmultiagentsystemscommunities in ane?ort to address the increasing costs of search, transaction, and coordination which follows from the increasing number of Internet-enabled distributed electronic markets. Furthermore, new technologies and supporting business models are - sulting in a growing volume of open and horizontally integrated markets for trading of an increasingly diverse set of goods and services. However, growth of technologies for such markets requires innovative solutions to a diverseset of - isting and novel technical problems which we are only beginning to understand. Speci?cally, distributed markets present not only traditional economic problems but also introduce novel and challenging computational issues that are not r- resentedin the classiceconomicsolution concepts.Novelto agent-mediatedel- tronic commerce are considerations involving the computation substrates of the agents and the electronic institutions that supports, and trading, and also the human-agent interface (involving issues of preference elicitation, representation, reasoningandtrust).Insum,agent-mediatedelectronictraderequiresprincipled design(fromeconomicsandgametheory)andincorporatesnovelcombinationsof theories from di? erent disciplines such as computer science, operations research, arti?cial intelligence and distributed systems. The collection of above-mentioned issues and challenges has crystallized into a new, consolidated agent research ?eld that has become a focus of attention in recent years: agent-mediated electronic commerce.

This book constitutes the thoroughly refereed post-conference proceedings of the 9th International Workshop on Agent-Mediated Electronic Commerce, AMEC IX, co-located with the Sixth International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS 2007, held in Honolulu, Hawaii, in May 2007, and the 5th Workshop on Trading Agent Design and Analysis, TADA 2007, co-located with the Twenty-Second AAAI Conference on Artificial Intelligence, AAAI 2007, held in Vancouver, Canada, in July 2007.

This volume presents 15 revised and selected papers from these workshops. The primary and complementary goal of both workshops was to continue to bring together novel work from diverse fields on modeling, implementation and evaluation of computational trading institutions and/or agent strategies. The papers originating from AMEC focus on a large variety of issues on auctions, negotiation, and strategic behavior in electronic marketplaces. The papers originating from TADA stem from the effort of the community to design scenarios where trading agent designers and market designers can be pitched against one another.