A short review is given on the discovery of the alpha 1-antitrypsin deficiency, a hereditary metabolic defect, in 1963, its biochemical identification, the recognition of its typical clinical manifestations and effects on lung physiology. Several genetic variants are mentioned. The gradual development of the concept of proteolytic digestion of lung elastin by excess of leucocyte elastase as a basic phenomenon in the pathogenesis of emphysema is discussed in some detail.