To the man on the street, genetics probably means all that DNA stuff about genes and the code of life which is continually, but not quite, being cracked in the newspapers. To Haig Papazian the subject is not only the recent biochemistry, but how this developed from Mendel's classic studies of garden peas and Darwin's erroneous but instructive idea of pangenesis, fostered around the turn of the century in the minds of a particularly brilliant cluster of workers like William Bateson, Thomas Morgan, and Walter Sutton. With this historical beginning, Papazian moves on to a close, perhaps too condensed biochemical summation, then branches out to the larger subject of populations, picking up Darwinian themes once more. Here the author puts the genes in their place in a world population pool, dealing dispassionately with such subjects as race, eugenics, sterilization, and the moral choices biologists face. For first-time readers there are probably easier introductions to gene structure and function. Papazian excels, however, in delineating current adventures and problems: extra-chromosomal inheritance, or the puzzle of differentiation (how cells get organized into special tissues). There is also a surprisingly painless mathematical analysis of gene frequencies. The reader may emerge charmed that he has understood such an unexpected result as the fact that the marriage between double first cousins involves the same degree of inbreeding as that of a marriage between a half brother and a half sister.