Preface to the Special Issue "History, Biology and Pathobiology of Prions: A Field of Renewed Hopes".

Research in the field of prion diseases has not only shed light on the mechanisms underlying transmissible spongiform encephalopathies (TSEs) but has also influenced the broader understanding of protein misfolding disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), and other tauopathies and synucleinopathies. Although prion diseases are rare and invariably fatal, they have provided an invaluable conceptual framework for the study of age-associated neurodegenerative disorders. On the occasion of the "Prion 2023" meeting in Faro, Portugal, which brought together leading experts in prion biology and neurodegeneration to discuss emerging data and evolving concepts, we put together a special issue on the topic to discuss new structural insights, diagnostic technologies, and the increasing recognition of prion-like mechanisms in a wide range of proteinopathies. This Special Issue features six comprehensive review articles that highlight key advances and ongoing challenges in the study of prions and related disorders.