This issue is a product of a special meeting ofthe International Psychogeriatric Association (IPA). The meeting, entitled “Outcome Methodologies for Pharmacologic Trials in Mild, Moderate, and Severe Alzheimer's Disease,” was held under the auspices of the IPA's Pharmacy and Therapeutics Comniittee on July 26, 1994, at the New York University Medical Center in New York City. The purpose of the meeting was to bring together leading scientists, clinicians, and regulatory personnel to address issues surrounding assessment of treatment efficacy in Alzheimer's disease (AD).