How and why have American labor unions grown in the century and a half since the industrial revolution? In this concise and illuminating history of the labor movement, Daniel Nelson traces the ebb and flow of union activity since the early nineteenth century. Rejecting an emphasis on individual leadership or the uniqueness of American “conditions,” he instead looks to three factors to explain labor’s record: the role of the autonomous worker, the threat of employer reprisals, and the influence of external forces such as government policy. His chief concern is to describe and document the historical experience, especially the erratically rising level of union membership from the close of the nineteenth century to the 1960s, and the reversal of that phenomenon in recent decades. Mr. Nelson devotes special attention to miners’ unions in the years up to the 1950s, to government policy in the New Deal years and after, and to the development of sophisticated anti-union employer strategies in recent years. The strength of Shifting Fortunes lies not only in the scope of its coverage but in its evenhanded portrayal of employer-worker relations.