This encyclopedic work presents a broad survey of the animal kingdom, with emphasis on the extensive series of evolutionary transformations that have led from ameba to man. The first volume contains 559 two-column pages of text and 144 pages of bibliography. The second volume contains 1,013 pages of illustrations, most of which are clearly labeled line cuts. In many instances, the drawings represent series of animals or of structures arranged along comparative-systematic lines to indicate the range and evolution of form in a given group. The book presents a stimulating review of the evolutionary concept in an easy, informal style.