Alan Kraut, a professor of history at American University, could not have chosen a better moment for the publication of Silent Travellers: Germs, Genes and the ‘Immigrant Menace’, for it coincides nicely with two trends in the United States. One is a morbid fascination with contagion, especially involving exotic, ‘killer’ strains like Ebola or the HIV virus. Hollywood has capitalised on it with a film, Outbreak, the tale of an American town accidentally infected by the Army’s germ-warfare programme, and the Army’s painful conclusion that it has to destroy the village to save it.

The other, more serious trend is a growing movement to exclude new immigrants from the United States. Readers should not be fooled by the book’s rather ambiguous title; this is not a book which blames foreigners for bringing disease to the New World, although it exhaustively documents many cases where precisely that happened. Rather, Kraut traces the hysterical, sometimes violent reactions of native-born Americans to epidemics rightly or wrongly attributed to newcomers.

Alas, Silent Travellers is not likely to ride any social waves onto the New York Times best-sellers list. What Kraut has produced is an interesting and, according to his own foreword, much needed account of how the United States