Context .- Three distinct patterns of pulmonary fibrosis, including usual interstitial pneumonia, fibrotic nonspecific interstitial pneumonia, and airway-centered fibrosis, can be identified on surgical lung biopsies. Objectives .- To compare the pathologic definitions, clinical and radiographic presentations, etiologies and differential diagnoses, treatments, and prognoses of usual interstitial pneumonia, fibrotic nonspecific interstitial pneumonia, and airway-centered fibrosis patterns, and to address the challenges and controversies related to pulmonary fibrosis. Data Sources .- Data were derived from published literature and clinical experience. Conclusions .- Although there may be overlap, identification of the dominant form of fibrosis in a particular case can provide a general category of disease and assist in identifying an etiology.