Since discovery of the importance of the R antien, more than 700 papers have appeared in the various fields of investigation which this discovery has opened. Many of these papers have been controversial or trivial, and no satisfactory digest of the literature has been available. Therefore, the appearance of a comprehensive, authoritative review of present knowledge and theories concerning the Rh factor is singularly welcome. In this volume the author has included clear, impartial, and well-illustrated discussions of the genetics, nomenclature, and serologic detection of the Rh antigens and antibodies; the clinical and pathologic manifestations of hemolytic disease, and the relation of Rh to transfusion reactions.