Contemporary Themes: Within this period, the immunology-driven paradigm linked serum antibodies, immune complexes, and immune cell–mediated injury to biliary destruction, shaping diagnostic and pathophysiological understanding across diseases. Histopathology defined the injury locus and progression, emphasizing intrahepatic bile-duct destruction and ductular proliferation as core mechanisms. Clinical recognition studies emphasized non-surgical diagnosis, serological cues enabling earlier management of primary biliary cirrhosis, and the evolving clinical taxonomy and differential diagnosis that mapped the cholangiopathy spectrum to guide classification. Historical Significance: Influential Works: Foundational anatomical mapping of the biliary ducts within the human liver established essential baselines for diagnosing and understanding cholangiopathies, guiding surgical approaches and later pathologic correlations. The 1965 work on primary biliary cirrhosis defined the disease concept and diagnostic framework, while serological studies introduced antibody-based distinctions shaping subsequent workups. The discovery of mitochondrial antibody in PBC and other diseases, along with pathology-based staging, catalyzed autoimmune hypotheses and standardized diagnostics and prognosis, influencing decades of research and care.