The first conference in this series, devoted principally to the interaction of positrons in gases, was held at York University, Toronto, in July 1981 immediately preceding the XII ICPEAC in Gatlinburg, and the proceedings were published in the Canadian Journal of Physics, volume 60 (1982). So successful was this meeting that the decision was taken to hold a second one around the time of XIII ICPEAC in Berlin in 1983. London was clearly a convenient location but, rather than the obvious choice of University College London in central London, the Organising Committee decided that the beautiful...