Practical Reasoning and Argument about Action -- Burden of Proof in Deliberation Dialogs -- A Generative Dialogue System for Arguing about Plans in Situation Calculus -- Dominant Decisions by Argumentation Agents -- A Model for Integrating Dialogue and the Execution of Joint Plans -- Practical Reasoning Using Values -- Persuasion and Negotiation -- Strategic Argumentation in Rigorous Persuasion Dialogue -- Assumption-Based Argumentation for the Minimal Concession Strategy -- Subjective Effectiveness in Agent-to-Human Negotiation: A Frame x Personality Account -- Argumentation Theory -- Dynamics in Argumentation with Single Extensions: Attack Refinement and the Grounded Extension (Extended Version) -- Arguing Using Opponent Models -- Realizing Argumentation in Multi-agent Systems Using Defeasible Logic Programming -- Computing Abductive Argumentation in Answer Set Programming -- Multi-Party Argument from Experience -- Applications and Emotions -- Using Ontology Modularization for Efficient Negotiation over Ontology Correspondences in MAS -- Applying Dialogue Games to Manage Recommendation in Social Networks -- Emotions in Rational Decision Making -- Using Personality Types to Support Argumentation -- Comparing Argumentation Frameworks for Composite Ontology Matching.

This book constitutes the thoroughly refereed proceedings of the 6th International Workshop on Argumentation in Multi-Agent Systems, held in Budapest, Hungary, in May 2009, in association with the 8th International Conference on Autonomous Agents and Multi-Agent Systems (AAMAS 2009). The 18 revised full papers were carefully reviewed and selected from numerous submissions and are organized in four topical sections on practical reasoning and argument about action; persuasion and negotiation; argumentation theory; and applications and emotions.