Aims : To describe the pathobiology, epidemiology, causes, diagnosis and treatment of idiopathic pulmonary fibrosis (IPF), the most common type of interstitial lung disease; to evaluate pulmonary fibrosis resulting from other diagnosable conditions, such as scleroderma, sarcoidosis and rheumatoid arthritis; to describe the epidemiology, biology, clinical presentation and treatment of this group of conditions; and to describe controversies in the diagnosis and treatment of rapidly progressive-interstitial lung diseases.