Research into prions and prion diseases has progressed at a rapid pace in recent years, and has shed new light on areas such as transmissible spongiform encephalopathies. Telling (Center on Aging, University of Kentucky) provides an overview of the pathogenesis, molecular biology, biochemistry, cellular biology, animal models, and immunology of prions, for researchers working in microbiology, molecular biology, and biochemistry, and for those in pharmaceutical and biotechnology companies. Specific topics include the prion protein in cell culture, binding and conversion reactions between prion protein isoforms, PrP deletion mutants, and targeting the murine PrP gene. Other subjects are transgenic mouse models of prion diseases, peripheral pathogenesis, and immunological advances in prion diseases.