This book represents the third in a series of International Conferences related to Alzheimer’s (AD) and Parkinson’s (PD) diseases. The first one took place in Eilat, Israel, in 1985; and the second one in Kyoto, Japan, in 1989. This book contains the full text of oral and poster presentations from the Third International Conference on Alzheimer’s and Parkinson’s Diseases: Recent Developments, held in Chicago, Illinois, U.S.A. on November 1-6, 1993. The Chicago Conference was attended by 270 participants. The Scientific Program was divided into nine oral sessions, a keynote presentation, and a poster session. The conference culminated in a Round Table Discussion involving all of the participants in the conference. The four and one-half day meeting served as an excellent medium for surveying the current status of clinical and preclinical developments in AD and PD. There were 59 oral presentations and 93 posters. This book incorporates a majority of both.