The Lung Tissue Research Consortium (L TRC) is a network of centers cooperating to harvest, process, and analyze lung tissue specimens to support scientific studies of the etiology and pathogenesis of lung diseases, especially chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis. The L TRC prepares collections of specimens, linked to clinical and genomic data, for widespread distribution to investigators for use in their research.