Konrad Lorenz (1903-1989) is an outstanding Austrian scientist, Nobel Prize laureate, one of the founders of ethology, the science of animal behavior. In this book, the author traces very interesting analogies in the behavior of various species of vertebrates and the species Homo sapiens, which is why the book is published in the “Library of Foreign Psychology” series. Arguing that aggression is an innate, instinctively determined property of all higher animals - and proving this with many convincing examples - the author comes to the conclusion: “There are good reasons to consider intraspecific aggression the most serious danger that threatens humanity in modern conditions of cultural, historical and technical development.” Books by K. Lorenz were published in Russian: “The Ring of King Solomon”, “A Man Finds a Friend”, “The Year of the Gray Goose”.