Although Seibutsu no Sekai (The World of Living Things), the seminal 1941 work of Kinji Imanishi, had an enormous impact in Japan, both on scholars and on the general public, very little is known about it in the English-speaking world. This book makes the complete text available in English for the first time and provides an extensive introduction and notes to set the work in context. Imanishi's work, based on a very wide knowledge of science and the natural world, puts forward a distinctive view of nature and how it should be studied. Imanishi's work is particularly important as a background to ecology, primatology and human social evolution theory in Japan. Imanishi's views on these subjects are extremely interesting because he formulated an approach to viewing nature which challenged the usual international ideas of the time, and which foreshadow approaches that have currency today.