This issue of Mineralogical Magazine – Journal of Mineral Sciences contains nine articles by distinguished mineralogists which were delivered as plenary lectures to the 18th General Meeting of the International Mineralogical Association held in Edinburgh in early September 2002. The IMA is the only truly international organization representing mineralogy, and is supported by subscriptions from 37 mineralogical societies world-wide. Its main activity is to hold a General Meeting every four years in one of the subscribing countries, and in 2002 the organization was handled jointly by a group based in Edinburgh and by the Mineralogical Society of Great Britain & Ireland. The organizers invited lecturers who we believed would provide an authoritative and exciting overview of the most vigorous areas of the science of mineralogy as we enter a new millennium. In this the lecturers have unquestionably succeeded and we are very grateful for the scholarship, time and effort that they have put into these presentations. Each article was checked by an expert, and I thank Ross Angel, Derek Bain, Bill Brown, Martin Lee, David Manning, Bryne Ngwenya and Alison Pawley for their help.