Argumentation as a field of inquiry has been attracting an increasing number of researchers from different areas. One of the main shared goals among these researchers is the pursuit of solutions to the many research problems found in the Knowledge Representation and Reasoning area of Artificial Intelligence using strategies akin to the commonsense approach displayed by humans. Practical applications of the basic research results have been gaining attention in several areas including in particular the Autonomous Agents and Multiagent Systems community. By the beginning of this decade, the need for a forum where these advances could be discussed in a specialized manner was recognized by the members of the argumentation community, leading to the decision of establishing a biennial conference with focus on the computational aspects of argumentation.

In September 2006, the First Conference on Computational Models of Argument was hosted, with resounding success, by the University of Liverpool; a similar response followed in May 2008 when the Second Conference on Computational Models of Argument was held in France, hosted by the Institut de Recherche en Informatique de Toulouse (IRIT).

This volume contains the papers forming the program of the Third Conference on Computational Models of Argument held in Desenzano del Garda, Italy, from Sept. 8th to 10th, 2010. This time the responsibility of hosting the conference was assumed by the University of Brescia. The papers in the volume address topics ranging from formal models of argumentation and the relevant theoretical questions, through algorithms and computational complexity issues, to the use of argumentation in several application domains, thus providing an up-to-date view of this vital research field.

The success of a conference depends on the contributions of many people. The organizers wish to thank the Steering Committee of COMMA for all the help received. We are deeply grateful to the members of the Program Committee, and additional reviewers, for the hard work of evaluating the submitted papers. Their reports and discussions greatly facilitated the final decisions that led to the content of this book, which includes two invited papers by prof. Gerhard Brewka and prof. Douglas Walton, 35 full papers and 5 short papers selected from 67 submissions.

We would like to thank Giovanni Perbellini for his contribution to the work of the Local Organizing Committee, Laura Folli for designing the conference logo and Diego Beda, Loretta Bettari, Luca Mori for their help concerning the venue of the conference. Finally, we gratefully acknowledge financial support from the Municipality of Desenzano del Garda and Taylor & Francis Group.

July, 2010

Pietro Baroni (General Conference Chair), Federico Cerutti (Local Organization Co-chair), Massimiliano Giacomin (Local Organization Chair), Guillermo R. Simari (Programme Chair)