Pulmonary emphysema is a disease which develops because of a localized imbalance between endogenous proteinase inhibitors and proteinases leaking from neurophils during phagocytosis at inflammatory foci within the lung. This volume not only reviews at a biochemical level what is known about the natural inhibitors and proteinases involved in connective tissue destruction within the lung, but also suggests novel methodologies for reestablishing proper enzyme-inhibitor balance, including the use of natural or synthetic inhibitors for supplementation or gene therapy.