This book is based on firsthand experience gained by the author and her research team during many years of experimental studies, supported by the analysis of abundant literature published between 1970 and 1999. It deals with the comparative assessment of ischemic and reperfusion injuries and their mechanisms in vitally important organs differing in their sensitivity to oxygen deficiency, metabolic activity, and provision with radical-generating and antioxidant system. A distinctive feature of the monograph, compared to previous studies in this field, is that attention is focused on the role of free-radical reactions, their place among other damaging factors (disturbances of energy metabolism, intensification of lipolysis and phospholipolysis, etc), a detailed analysis of mechanisms responsible for the formation of free radicals during ischemia (the roles of electron transport pathways, radical-generating enzymes, macrophages, endothelial cells, etc) and a general review of modern methods of antiradical and antischemic therapy. None of the books published to date is characterised by such an approach to the problem.