Interstitial Lung Disease is divided into three sections. The Clinical Approach section provides the basis for recognizing the key features that allow a specific diagnosis to be achieved. The section dedicated to Basic Mechanisms emphasizes the many advances in genetics and cellular and molecular biology that have greatly expanded our understanding of the biological processes involved in the pathogenesis of ILD. The third section titled Clinical Entities describes the clinical manifestations, radiologic patterns, histopathological features, and management of the specific process