When I began studying for my PhD, I knew exactly what field I wanted to work in. It was a subfield of Artificial Intelligence (AI) that was known as Distributed AI (DAI). In DAI, we studied how a number of (semi-)autonomous problem solving systems known as ‘agents’ could be made to cooperate and coordinate their activities to produce effective overall system behaviour (Bond and Gasser, 1988). At the time, not many people were working in distributed AI (only two books had been published on the subject). I found that when I talked about my research, I had to repeatedly explain what ‘agents’ were all about. It was depressing business. More than once, I wished I had gone into a more glamorous area of research - the expert systems people were getting all the glory.