This book represents the fourth ina series of international conferences related to Alzheimer's (AD) and Parkinson's (PO) diseases. The first one took place in EHat, Israel in 1985; the second in Kyoto, Japan, in 1989; and the third in Chicago, IL, USA in 1993. This book incorporates the proceedings of the Fourth International Conference on Pro- gress in Alzheimer's and Parkinson's Diseases, held in EHat, Israel, on May 18-23, 1997. This Conference was the 41st in the series of annual OHOLO Conferences sponsored by the Israel Institute for Biological Research (IIBR). It was also conducted...