About the book: 1976 / The brochure discusses the causes of the extinction of ancient reptiles and mammals, as well as some animals of our time. The author shows the leading role in the extinction of ancient reptiles and mammals of the biotic factor, the constant displacement of archaic types by new ones, without at all denying the importance of abiotic conditions, changes in which in some cases accelerated the process of extinction. Gabunia Leonid Kallistratovich (born 09/03/1920) - Soviet paleontologist, academician of the Academy of Sciences of the Georgian SSR (since 1969). Born in Irkutsk. Graduated from the mining department of the Georgian Industrial Institute (1943). Since 1947 he worked at the Institute of Geology and Mineralogy of the Academy of Sciences of the Georgian SSR, where he specialized in paleontology. Since 1951 - at the Institute of Paleobiology of the Academy of Sciences of the Georgian SSR (since 1977 - director). The main scientific works are devoted to the study of the Hipparion fauna, the Benar fauna of Oligocene vertebrates, the Belomechetsky fauna of Middle Miocene mammals, the study of dinosaur tracks, problems of extinction and progress in paleobiology. Member of the American Society of Vertebrate Paleontology ( With 1970).