This is volume 1, issue 1, of a new Series Hematologica edited in Denmark. This issue represents a formidable discussion of human serum components grouped on the basis of genetic features. Sections include haptoglobins, transferrin, Gc, Ag, Lp, Ti, and the Gm and Inv systems. Nomenclature and concept will be difficult for the uninitiated. This first issue will be of great interest to geneticists, immunologists, immunologically-oriented hematologists, and others of similar persuasion.