In the first hundred years of its history, immunology was mired in the problems of species and specificity both in research and in practice. The old botanical dispute about the nature of species, which has its roots in classical Western thought, reappeared in the late nineteenth century in the disputes of the bacteriologists, and subsequently of their students, the immunologists, immunochemists, and blood group geneticists. The argument centered on the question of unity and diversity.

Proponents of unity insisted on the continuity of nature, while those of diversity emphasized the separation and definition of individual species. In the course of this controversy, Pauline Mazumdar argues, five generations of scientific protagonists waged a bitter intellectual war that defined the structure of immunological thought during the first half of the twentieth century.

Their science was designed only in part to wrest an answer from nature: it was at least as important to wring an admission of defeat from their opponents.

One of the key figures in the debate was the Austrian immunochemist Karl Landsteiner, whose career provides the central focus for Mazumdar's account. His unitarian views excluded him from promotion within European institutions, where the specificity and pluralism espoused by Robert Koch and Paul Ehrlich were entrenched. Landsteiner himself was forced into a kind of exile at Rockefeller University in New York.

Though Landsteiner won a Nobel prize for his work, his inability to gain more widespread acceptance of his views caused him to view his life as a failure.