The impact of the industrial revolution on the social structures of industrialized nations posed a difficult challenge to the Catholic Church and its Popes. In the struggle for human and economic status, should the Church side with the new working class or with capitalist barons who, along with the old aristocracy, identified themselves as upholders of Christian civilization? In this history of papal social teaching, Joe Holland tells how the popes at first backed the status quo. Then, with the accession of Pope Leo XIII in 1878, a seismic shift took place. Leo’s encyclical Rerum novarum was the first authoritative Church voice to declare that laboring people have rights–the right to fair wages, to decent living conditions, the right to organize labor unions and even to strike. Henceforth the notion of civilization, at least for the Church, would be grounded in the lives and aspirations of working people. Modern Catholic Social Teaching traces this historic shift as it played out in the writings of Leo and the popes who followed him: Pius X, Benedict XV, Pius XI, and Pius XII. These popes supported Leo’s encyclical and even elaborated it.