Monsignor Luigi Giussani (1922–2005), who founded the lay renewal movement ‘Communion and Liberation’ that has now spread around the world, wrote a doctoral dissertation in the mid-1960s on Reinhold Niebuhr. That research spun off into this book, published in Italian in 1968. While it will not replace the comprehensive studies by E. Brooks Holifield and Gary Dorrien, Giussani's well-informed survey provides a rare glimpse from someone outside the United States commenting on the development, strengths and weaknesses of his subject. Although it includes brief snippets on many figures, its real interest lies in extensive treatments of the ones who obviously most impressed Giussani. First is Jonathan Edwards, singled out for combining a high estimate of divine sovereignty and an insistence on the experiential character of life-changing conversion. Giussani finds Walter Rauschenbusch too optimistic about the human ability to overcome the inheritance of sin, but commendable for stressing ‘the social dimensions of Christian experience’ (p. 93). He also describes Paul Tillich's notion of ‘correlation’ as particularly suited to an American rapprochement between Christianity and modern culture. But his real fascination is Niebuhr, whom Giussani finds promoting the right kind of realism about persons actually enmeshed in history. To Giussani, Niebuhr synthesised what was best in American theology: Edwards's elevated view of divine sovereignty, the later Edwardseans' understanding of disinterested benevolence, revivalists' concentration on personal conversion, and liberals' sensitivity to modern life. His reasons for favouring Niebuhr should help other students of American theological development to make their own judgements with greater self-awareness.