We express our sincere gratitude to Barry Reisberg, M.D., and Gerald Oppenheim, M.B., B.S., F.R.A.N.Z.C.P., for their guest editorship in compiling a group of important papers on the clinical course of Alzheimer's disease, as well as the methodological implications of clinical changes in Alzheimer's disease for pharmacologic trials. The papers were presented initially at a special symposium of the IPA Fifth International Congress in Rome, Italy, August 18–23, 1991. This issue of International Psychogeriatrics is our second supplement within a year, derived from important presentations at IPA meetings and deemed worthy of dissemination to the wide IPA audience.