Argumentation in multi agent systems : first international workshop ArgMAS 2004 New York NY USA July 19 2004 : revised selected and invited papers The theory of argumentation is a rich interdisciplinary area of research involving philosophy communications studies linguistics psychology and logics. Its techniques have found a wide range of applications in both theoretical and practical branches of artificial intelligence and computer science. Multi agent systems theory has picked up argumentation inspired approaches and specifically argumentation theoretic results from many different areas. Researchers in argumentation and multi agent systems are currently enjoying a unique opportunity&nbsp;to integrate the various understandings of argument into a coherent and core part of the functioning of autonomous computational systems. This book originates from the First International Workshop on Argumentation in Multi Agent Systems ArgMAS 2004 held in New York NY USA in July 2004. Besides 12 selected revised full papers taken from the workshop 4 additional papers by key people in the area to round off overall coverage of the relevant topics. The papers address the following main topics: foundations of dialogues belief revision persuation and deliveration negotiation and strategic issues