The most vital task of the present age is to formulate a social basis for civilization, to dethrone economic ideals and replace them by human ones. To the biologist who is not afraid of being a humanist as well, the essence of human life is seen in social relationships. Among the essays in this provocative book, which develop this theme are: The uniqueness of man, Climate and human history, The courtship of animals, Life can be worth living, Darwinism today, War as a biological phenomenon.