This two-volume book contains selected papers from the international conference 'Groups 1993 Galway/St Andrews' which was held at University College, Galway in August 1993. The wealth and diversity of group theory is represented in these two volumes. Five main lecture courses were given at the conference. These were 'Geometry, Steinberg representations and complexity' by J. L. Alperin (Chicago), 'Rickard equivalences and block theory' by M. Broué (ENS, Paris), 'Cohomological finiteness conditions', by P. H. Kropholler (Queen Mary and Westfield College, London), 'Counting finite index subgroups', by A. Lubotzky (Hebrew University, Jerusalem), 'Lie methods in group theory' by E. I. Zel'manov (University of Wisconsin at Madison). Articles based on their lectures, in one case co-authored, form a substantial part of the Proceedings. Another main feature of the conference was a GAP workshop jointly run by J. Neubüser and M. Schönert (Rheinisch-Westfalische Technische Hochschole, Aachen). Two articles by Professor Neubüser, one co-authored, appear in the Proceedings. The other articles in the two volumes comprise both refereed survey and research articles contributed by other conference participants. As with the Proceedings of the earlier 'Groups-St Andrews' conferences it is hoped that the articles in these Proceedings will, with their many references, prove valuable both to experienced researchers and also to new postgraduates interested in group theory.