This book constitutes the refereed proceedings of the 15th International Conference on Principles and Practice of Multi-Agent Systems, PRIMA 2012, held in Kuching, Sarawak, Malaysia, in September 2012. The conference was collocated with the 12th Pacific Rim International Conference on Artificial Intelligence, PRICAI. The 17 revised full papers presented were carefully reviewed and selected from 42 submissions. The papers are organized in topical sections on foundations, auctions and negotiation, coalition formation and teamwork, norms and institutions, and applications.

This book constitutes the thoroughly refereed post-workshop proceedings of three workshops held in conjunction with the 10th Australian Joint Conference on Artificial Intelligence in Perth, Australia, in December 1997.
The 17 revised full papers presented were carefully reviewed for inclusion in the book. The book is divided into sections on formal methods of agency, reasoning agents, communication and coordination, social interaction, and practical issues for distributed artificial intelligence systems.

The agents approach is not just another abstract computing paradigm, but has matured during recent years into a booming research area and software engineering technology which holds great promise for the design and application of complex distributed systems.
This book presents 12 revised full chapters grouped around 3 main topics in intelligent agent systems; agent architectures, formal theories of rationality and cooperation and collaboration. Among the topics addressed are software agents, BDI architectures, social commitment, believable agents and artificial life. The book is based on the Workshop on Theoretical and Practical Foundations of Intelligent Agents held at the Fourth Pacific Rim International Conference on Artificial Intelligence in Cairns, Australia, in August 1996.

AI 2008, the 21st Australasian Joint Conference on Arti?cial Intelligence, was, for the ?rst time, held in New Zealand, in Auckland during December 1-5,2008. The conference was hosted by Auckland University of Technology. AI 2008attracted 143 submissions from 22 countries, of which 42 (29%) were accepted as full papers and 21 (15%) as short papers. Submissions were subject to a rigorous review process. Each paper was reviewed by at least three (often four, andinonecase, six)membersoftheProgrammeCommittee.Authorscould then provide a "rebuttal" to these reviews. The Senior Programme Committee members coordinated discussion on the papers to provide a recommendation of acceptance or rejection to the Programme Committee Co-chairs. Both full papers and short papers were presented at the conference. We would ?rst like to thank all those who submitted papers to AI 2008. Specialthanks to the ProgrammeCommittee members for their detailed reviews completedinatimelymanner, andtotheSeniorProgrammeCommitteefortheir consideredjudgements andrecommendationsonthepapers.We aresureauthors would like to know that the rebuttal and subsequent discussion phases made a di?erence to the outcome in numerous cases. We are con?dent that this process has improved the decision making for ?nal paper selection, and that the overall quality and reputation of the conference is enhanced as a result. Thanks also to EasyChair for the use of their conference management system to facilitate this complex process and the preparation of these proceedings.