Over the past decade, it has been demonstrated that Alpha1-Antitrypsin (AAT) is a broad-spectrum anti-inflammatory, immunomodulatory, anti-infective and tissue-repair molecule. As a consequence, Alpha1-Antitrypsin Deficiency is a fascinating condition, affecting people at all ages, from neonates to the elderly, that requires multidisciplinary approaches. A greater understanding of the science underpinning pathophysiological mechanisms is now directly translating into an increasing number of clinical studies, new pharmacological formulations, new patent applications and the search for alternative sources of AAT to meet the expected demand for treating a large number of diseases, inside and outside the context of AAT deficiency. Medical professionals need an updated and intelligible text to discover and approach it in all the aspects of its manifestations, to properly suspect, diagnose, manage and treat it.