Continuing the series of workshops begun in 1996 (Luck, 1997; Doran et al., 1997; d'Inverno et al.,1997; Fisher et al., 1997) and held in each of the two years since (Luck et al., 1998; Aylett et al., 1998;Binmore et al., 1998; Decker et al., 1999; Beer et al., 1999), the 1999 workshop of the UK SpecialInterest Group on Multi-Agent Systems (UKMAS'99) took place in Bristol in December. Chairedand organised by Chris Preist of Hewlett Packard Laboratories, with support from both HP and BTLaboratories, the workshop brought together a diverse range of participants, from the agentcommunity in both the UK and abroad, to discuss and present work spanning all areas of agentresearch. Although dominated by computer scientists, also present at the meeting were electronicengineers, computational biologists, philosophers, sociologists, statisticians, game-theorists, economists and behavioural scientists, with both academia and industry well represented. Indeed,numbers attending these workshops continue to grow, reflecting the continued and rising interestin agent-based systems. The meeting truly demonstrated the wider view of what the term “agency”implied to research in other disciplines and the questions raised at the end of presentations were apertinent reminder of the diversity of the audience.