Most of the world's experts on prions met for a workshop in Erice in August 1996. The aim of the workshop was to discuss the fundamentals of the science ofprions. It was for- tunate that so many could be present given the pressure that they were under because of the data presented in March 1996, indicating that Bovine Spongiform Encephalopathy, BSE or Mad Cow Disease, had penetrated the species barrier and was beginning to cause a new dis- ease in humans--the new variant ofCreutzfeldt-Jakob Disease, nvCJD. This important and urgent subject became an additional major topic at the workshop. This is a book containing most of the talks plus the abstracts of those unable to find time to write up their talks. Almost all papers were written in the spring and summer of 1997 and contain material added after the workshop; thus Bob Will's paper on the new variant of cm contains data up to July 1997 and four contributions arrived in October 1997. In addition to the talks given at our workshop, there was a special joint session with the Planetary Emergencies Workshop where many distinguished scientists, including three Nobel laureates, discussed major issues affecting our planet. Six talks were given by us to this other workshop, five about prions, BSE, and nvCJD, and one on the broader issue of new epi- demics by Luc Montagnier. Although most of the talks concerned research issues, there were a few special talks.

Table of Contents:
— Guide to the Talks.- Polymorphic Genotype Matching in Acquired Creutzfeldt-Jakob Disease: An Analysis of Donor/Recipient Case Pairs.- Human Prion Protein Gene Mutation at Codon 183 Associated with an Atypical Form of Prion Disease.- Fatal Familial Insomnia: A Human Model of Prion Disease.- Mechanisms of Phenotypic Heterogeneity in Human Prion Diseases.- Transgenic Mice with Neuron-Specific Expression of a Hamster Prion Protein Minigene Are Susceptible to Hamster Scrapie Agent.- The Use of Transgenic Mice in the Investigation of Transmissible Spongiform Encephalopathies.- Large-Scale Sequencing of Human, Mouse, and Sheep Prion Protein Genes.- Electron Microscopy in Prion Research: Tubulovesicular Structures Are Not Composed of Prion Protein (PrP) but They May Be Intimately Associated with PrP Amyloid Fibrils.- Familial Prion Diseases Modeled in Cell Culture.- Yeast Approach to Protein “Prionization”: SUP35-[PSI] System.- Prions of Yeast: Genetic Evidence that the Non-Mendelian Elements, [PSI] and [URE3] Are Altered Self-Replicating Forms of Sup35p and Ure2p, Respectively.- Early Clinical Detection of Brain Diseases in Animals.- Prion Biology and Diseases — Fatal Conformations of Proteins during a Journey from Heresy to Orthodoxy.- New Variant Creutzfeldt-Jakob Disease.- The Molecular Basis of Cellular Dysfunction in Prion Diseases.- Presenilin Proteins and the Pathogenesis of Early-Onset Familial Alzheimer’s Disease: ?-Amyloid Production and Parallels to Prion Diseases.- Polyene Antibiotics in Experimental Transmissible Subacute Spongiform Encephalopathies.- Scrapie Pathogenesis in Brain Grafts.- Structural Properties of Recombinant Human Prion Protein.- Autonomous Folding and Three-Dimensional Structure of the Carboxy-Terminal Domain of the Mouse PrionProtein, PrP (121–231).- Protease-Resistant Prion Protein Formation.- Biophysical Studies on Structure Structural Transitions and Infectivity of the Prion Protein.- Amyloidogenesis in Transmissible Spongiform Encephalopathies.- Neuronal Degeneration and Cell Death in Prion Disease.- Clinical, Pathological, and Molecular Characterization of Gerstmann-Sträussler-Scheinker Disease in the Indiana Kindred (PRNP F198S).- Studies on the Pathogenesis of Scrapie and the Purification of Scrapie Agent in the Hamster Model.- PrP Peptides as a Tool to Investigate the Pathogenesis of Prion Protein Amyloidoses.- Properties of the Prion Proteins in Creutzfeldt Jakob Disease Patients Heterozygous for the E200K Mutation.- Strain Variation in Scrapie and BSE.- Transmission Studies of Fatal Familial Insomnia.- Molecular, Genetic, and Transgenetic Studies of Human Prion Disease.- Molecular Biology of Prion Propagation.- Ultrastructural and Immunocytochemical Studies on Prion Pathogenesis.- Overview of the BSE Epidemic.- Assessing Risks of BSE Transmission to Humans.- Human Activities Are Causing Selection of Pathogenic Agents.- Pathogenic Similarity of Slow Infections, Induced by Prions and Virions.- Protein Folding and Misfolding.- CJD Risk Factors: Analysis of 104 Patients.- Concluding Talk: Prions from a Physicist’s Viewpoint — Is the ‘Protein Only’ Hypothesis Correct?.- List of Speakers.- Names and Addresses of Participants.