There is need for an extensive monograph concerning the monocyte but this is not it. Of the 90 pages of text, 66 are devoted to a discussion of the monocytic leukemias and leukemic reticuloendotheliosis, and the coverage of these conditions is excellent. On the other hand, the section on the normal monocyte hardly does justice to the considerable information available concerning the structure, chemistry, and physiology of the monocyte. The entire topic of the monocyte in immunity is covered in two paragraphs. The section on monocytosis is covered in a page and a half and has not been recently updated.