The main message from this book is that the different protein aggregation processes may all be amenable to a small number of intervention steps based on a common theme of the modulation of production, turnover and deposition of the corresponding disease gene products. The next few years will prove critical in evaluation the possibilities of rational therapeutic strategies towards regaining the loss of function through the amelioration of the abnormal gain of function.

This volume contains the proceedings of the ninth "Colloque medecine et recherche" of the Fondation IPSEN devoted to research on Alzheimer's disease. This symposium was held in Lyon on June 21, 1993, on the topic, "Amyloid Protein Precursors in Development, Aging and Alzheimer's Disease". The choice of this venue and of this particular subject was not a matter of chance. As far as the history of medicine and neurology is concerned, Lyon is doubtless one of the most famous cities in France and the F ondation IPSEN had to organize one of its meetings in this city which has been regarded for centuries as a major crossroads. Regarding the topic, the amyloid story is at the center of the debate in the field of Alzheimer's studies. For nearly 10 years, "alzheimerology" has more or less been intertwined with "amyloidology". The purification and the sequencing of the beta/ A4 peptide in amyloid congophilic angiopathy (Glenner and Wong 1984) and in Alzheimer's disease (Masters et al. 1985) were the first steps toward the numerous successes realised in the last few years. The discovery of the amyloid precursor protein (APP), the localisation of its gene on chromosome 21 and the sequencing of its cDNA in 1987 (Kang et al. 1987; Goldgaber et al. 1987; Robakis et al.