In 1891, officers of the United States Public Health Service began examining immigrants at the nation''s borders for "loathsome and dangerous contagious diseases." First introduced as a means to screen out those who posed a threat to public health, the examinations were soon described by officials as a way of denying entry to applicants who could not work and would, therefore, be a burden on society. But historian Amy Fairchild has unearthed a curious fact about this ubiquitous rite of immigration—it was rarely undertaken to exclude immigrants.

In Science at the Borders, Fairchild retells the immigrant story, offering a new interpretation of the medical exam and the role it played in the lives of the 25 million immigrants who entered the US. She argues that the vast assembly line of flesh and bone served as a kind of initiation into the life of the new working class, one that would introduce men and women from the villages of eastern Europe and elsewhere to the norms and conventions of the factory floor. What the overwhelming majority of immigrants endured at Ellis Island and other entry points to the United States was, according to Fairchild, part of a process of induction into American industrial society.

Against this backdrop Fairchild also explores the southern border of the United States and the West Coast where the exam did, in fact, serve to exclude. Throughout, Fairchild conveys the humanity of the story, offering detailed accounts of individual immigrants confronting a large scientific and medical bureaucracy.