This book is based on our two books, published in the USSR and translated in a number of other countries Conservation of living nature: problems and perspectives (1983) and The levels of conservation of living nature (1985). It differs from the vast majority of the numerous books on conservation and environment, which are mainly devoted either to specific problems of conservation of certain taxons, or to problems of conservation of prescribed regions, or to general issues of environmental conservation in toto, while the problems of the conservation of living nature are represented only to a small degree. Our book is one of the volumes - at present not numerous - that place a high value on the diversity ofliving nature as the basis for the existence and development of mankind on the Earth. Living nature, besides its own intrinsic value, at all times was, is now and will ever remain the sole, unique and indispensable resource and provider for mankind.