This is the first full length study for almost two hundred years of the Scottish Evangelical Calvinist minister John Erskine (1721–1803). There are recent accounts of the Popular party in the Church of Scotland, including Erskine, by John R. McIntosh and Ned C. Landsman (who also wrote the ODNB article), but this is an original and well-researched intellectual biography of Erskine that adds considerably to our knowledge and that will appeal to a range of readers with interests in eighteenth-century Scottish theology and religious culture, Evangelicalism, transatlantic relations and the circulation of books. Yeager provides chapters on Erskine's decision to train for the ministry, influenced by the Cambuslang and Kilsyth revivals and the impact of George Whitefield in Scotland; his methods as preacher, in comparison with those of William Robertson and Hugh Blair; his orthodox Calvinist theology, modified by Evangelical emphasis on the need to preach the Gospel to all; his controversial writings against both John Wesley's anti-Calvinism and Roman Catholicism; his American friendships, notably (by correspondence) with Jonathan Edwards, and his support of the American side in the Revolution; and his role as disseminator of books. Yeager is clear that Erskine's importance is not as preacher, theologian or controversialist (though he has interesting things to say about all these roles) but as propagator of Evangelical Calvinist books and ideas. Through the study of booksellers' catalogues, Erskine's manuscript correspondence, and his editions and published recommendations of other writers' works, Yeager spells out in fascinating detail Erskine's responsibility for publishing Edwards's works in Scotland, supplying thousands of English and Scottish books to American ministers and colleges, recommending reading to English Baptists, sending American and British books to Holland, attempting (unsuccessfully) to get English and American readers to study Dutch theology, and urging others to write in defence of Evangelical Calvinist principles. Like his bête noire Wesley (though Yeager does not make this comparison) Erskine saw that to be widely read books had to be affordable. The main weakness of this study is Yeager's tendency to repeat the claim that Erskine's life's work is a manifestation of the Enlightenment, a term that is in danger of losing all meaning. The account of Erskine's attack on Wesley, though it shows convincingly why Methodism failed in Scotland, does not properly explain why Wesley thought that the doctrine of predestination was poisonous.