The powers of seeing, hearing, re membering, distinguishing, judging, reason ing, are speculative powers; the power of ex ecuting any work of art or labour is active power. Thomas Reid I Some causal efficacy is due to persons. And, some of the causal efficacy due to persons is imparted by, not merely to, them. Further, some of the causal efficacy due to persons and imparted by them is imparted by and not merely to their physical, active bodies. Otherwise there is no agency. I will assume, with everyone at the outset, that the world contains agency of the kind found in some of a person's comings and goings, movings and changing of things. Agency is exhibited in more and in less sophisticated forms, that is, in any sophisticated, artful activity and in less complex, non-articulate physical activities. In both there appears to be more than mere causal efficacy imparted to the environment by a person. In sophisticated agen cy activities are organized, guided, purposive and purposeful comings and goings, movings and changes. And purpose is not absent in less soph isticated purposive activities of active creatures. So I shall argue in what follows. Now is the time for introducing the themes, topics, and issues to be considered, and the plan and purpose in them.

A collection of essays is concerned with deepening our understanding of the notion of intention.

Human beings act together in characteristic ways that matter to us a great deal. This book explores the conceptual, metaphysical and normative foundations of such sociality. It argues that appeal to the planning structures involved in our individual, temporally extended agency provides substantial resources for understanding these foundations of our sociality.

This title was first published in 2001. Legal systems are posited on the assumption that people are rational intentional agents who can choose to follow or break the law. This book connects the common interests of lawyers and philosophers in the meaning of intention and its relation to responsibility in legal, moral and political contexts.

Intention is one of the masterworks of twentieth-century philosophy in English. First published in 1957, it has acquired the status of a modern philosophical classic. The book attempts to show in detail that the natural and widely accepted picture of what we mean by an intention gives rise to insoluble problems and must be abandoned. This is a welcome reprint of a book that continues to grow in importance.

The leading edge of computer science research is notoriously ?ckle. New trends come and go with alarming and unfailing regularity. In such a rapidly changing ?eld, the fact that research interest in a subject lasts more than a year is worthy of note. The fact that, after ?ve years, interest not only remains, but actually continues to grow is highly unusual. As 1998 marked the ?fth birthday of the International Workshop on Agent Theories, Architectures, and Languages (ATAL), it seemed appropriate for the organizers of the original workshop to comment on this remarkable growth, and re ect on how the ?eld has developed and matured. The ?rst ATAL workshop was co-located with the Eleventh European Conference on Arti?cial Intelligence (ECAI-94), which was held in Amsterdam. The fact that we chose an AI conference to co-locate with is telling: at that time, we expected most researchers with an interest in agents to come from the AI community. The workshop, whichwasplannedoverthesummerof1993,attracted32submissions,andwasattended by 55 people.ATAL was the largest workshop at ECAI-94, and the clear enthusiasm on behalfofthecommunitymadethedecisiontoholdanotherATALworkshopsimple.The ATAL-94proceedingswereformallypublishedinJanuary1995underthetitleIntelligent Agents, and included an extensive review article, a glossary, a list of key agent systems, and — unusually for the proceedings of an academic workshop — a full subject index. Thehighscienti?candproductionvaluesembodiedbytheATAL-94proceedingsappear to have been recognized by the community, and resulted inATAL proceedings being the most successful sequence of books published in Springer-Verlag s Lecture Notes in Arti?cial Intelligence series.