Marston Bates the scientist, established a good reading public with books like The Nature of Natural History (1950), and later, his study of the tropics Where Winter Never Comes. Here, through the opportunity afforded him by a Rockefeller Foundation grant, he tackles the problem of world population with a naturalist's insight that establishes the connecting links between the many fields involved and in his own statement of these most devastating problems, he adds greatly to the clarification of issues. It is wide territory that he sets out to cover. To encompass it, he discusses the problem of public health, birth, death and migration- in terms of resources and purposes- the world over and in the light of history. An initial chapter on the population problem gives what records of man's numbers there are (and have been in the past), population trends and the relative meaning of ""density"", the basic qualities of human nature, and some of the qualities of cultural evolution. On these last two topics hang the core of his thesis- that culture is the soil from which our actions grow and that it is improvable. Further material- on the different kinds of man, his relation to the means of subsistence, reproduction, birth control, death, war, famine, disease, migration, health improvement and eugenics- is related in an anthropological rather than a coldly technical context. Each of the topics is inevitably linked to the social mind of the peoples involved- whether English or American or Pygmies- and with a view towards directly improving action where it is possible. Definitely stimulating reading, and with its popularity, it may reach a wider audience than the more scholarly parallels.