Few scholars have studied American theological liberalism with as much acumen and depth as has Gary Dorrien. From his early books such as Soul in Society: The Making and Renewal of Social Christianity (Fortress, 1995) to his work on the Black Social Gospel, The New Abolition: W.E.B. Du Bois and the Black Social Gospel (Yale, 2015) and Breaking White Supremacy: Martin Luther King Jr. and the Black Social Gospel (Yale, 2019), Dorrien persuasively argues for the retrieval of American liberal theology for our time. His latest book, The Spirit of American Liberal Theology, succeeds in synthesising much of this scholarship into one volume.

The core of Dorrien's book comes from his three-volume The Making of American Liberal Theology series published by Westminster John Knox Press between 2001 and 2006. The Spirit of American Liberal Theology represents an abridgment of these volumes into a readable book that will be of great use to scholars and students in interpreting what Dorrien calls the most important theological tradition produced in the U.S.

Dorrien restates an argument from his previous studies that liberalism represents ‘a third way between orthodox authority religion and skeptical disbelief’ (p. 1). While indebted to nineteenth-century developments in German biblical, theological and historical scholarship, American theological liberalism was noteworthy for its strong commitment to social justice, building upon the bedrock of earlier postmillennial evangelical Protestantism.

The book's heart rests in its first ten chapters, which carry the story of American theological liberalism from its eighteenth-century roots through the mid-twentieth century. Chapters 1 through 4 outline American theological liberalism's origins in New England Unitarianism. He describes how ministers such as William Ellery Channing, Ralph Waldo Emerson and Theodore Parker laid a template for the development of liberal theology in New England Congregationalism and, by the end of the nineteenth century, within American Protestantism more broadly. Dorrien emphasises that pioneers of American liberal theology such as Horace Bushnell, Newman Smyth, Henry Ward Beecher, Theodore Munger and Washington Gladden were pastors, preaching a gospel-centric theology balancing reason and religious experience.

Chapters 5 through 10 highlight liberalism's development in the first half of the twentieth century, shifting from church pulpits to academics in universities and theological seminaries. Dorrien summarises important late nineteenth- and early twentieth-century traditions of liberal theology that emerged from academic institutions such as Union Theological Seminary (NY), the University of Chicago and Boston University, focusing on how these traditions contributed to the growth of social Christianity. These chapters culminate with chapter 10, which focuses on the legacies of Howard Thurman and Martin Luther King Jr.

Discussing white Social Gospel leaders such as Gladden, Shailer Mathews and Walter Rauschenbusch alongside Black Social Gospelers such as Richard Wright Jr., Dorrien shows how these two traditions met in Martin Luther King Jr. He provides an overview of scholars such as Mordecai Johnson, Benjamin Mays and Howard Thurman, as well as discussing the legacy of Boston Personalism, associated with Edgar S. Brightman, L. Harold DeWolf and Walter Muelder. Dorrien surmises that King's ‘religious philosophy remains the most luminous example of taking Black American faith and experience as a privileged point of departure, and of making a liberal-liberationist argument steeped in the Black freedom tradition that draws upon the entire history of Christian and modern thought’ (pp. 338–39). In Dorrien's view this makes King the first authentic American liberation theologian.

The final five chapters focus on late twentieth- and early twenty-first-century liberalism, describing an assortment of liberal traditions from the mid-twentieth century to the present. Dorrien includes discussions of process theologians such as John Cobb and Marjorie Suchocki, liberation theologians such as Rosemary Ruether and James Cone, Catholic theologians such as David Tracy and constructive theologians such as Catherine Keller and John Thatamanil.

Writing a one-volume narrative of this nature is no easy task, and there are omissions in certain areas. I wish Dorrien had included sections of important early twentieth-century women such as Georgia Harkness and Vida Dutton Scudder, persons he's discussed in greater detail in his previous work. Scudder's Anglo-Catholicism, combined with her strong socialist beliefs, reflects a very different trajectory of American liberal theology that needs to be explored in greater depth.

Dorrien takes a big-tent approach in defining theological liberalism, and a reader might be baffled by the names he includes in the liberal fold – especially as many of these theologians would not necessarily embrace that label. This is especially the case in the last five chapters where it can be difficult to find cohesion that ties the scholars he discusses to theological liberalism. In the book's final chapter, however, he offers a helpful summation, identifying seven types of liberal theology: an ‘experiential-evangelical’ pietistic liberalism represented by Henry Ward Beecher and William Newton Clarke; a ‘socioethical theology’ connected to the Social Gospel movement and represented by Walter Rauschenbusch and Martin Luther King Jr.; mystical liberalism, committed to a strong interfaith component, represented by Howard Thurman; Roman Catholic liberalism represented by David Tracy; naturalistic liberalism represented by Shailer Mathews and other theologians from the University of Chicago; process theology liberalism represented by John Cobb and constructive theology liberalism represented by Catherine Keller and John Thatamanil (pp. 486–87).

Dorrien concedes that he sees the first two strands as being the most successful in reaching audiences beyond the academy, noting the popularity of figures such as Marcus Borg and John Shelby Spong. Echoing his The Making of American Liberal Theology series, he concludes with the assertion that the best of the liberal tradition must maintain its connections with Christian tradition while also being open to the realities of the contemporary world. Dorrien notes that the future of the tradition depends on how it engages two questions: ‘How are the best aspects of religious traditions sustained? How are inclusive, open-ended religious traditions created and nurtured?’ (p. 487).

Does liberal theology have a future in the twenty-first century? At a time when many liberal denominations and theological seminaries face declining numbers and dwindling financial assets, the current religious landscape looks very different from the one confronted by Walter Rauschenbusch, Reinhold Niebuhr, Howard Thurman and Martin Luther King Jr. The Spirit of American Liberal Theology, however, reminds us of the importance of theological liberalism for interpreting the history of American theology and for seeing ways this tradition has played a critical role in U.S.-based movements of social change.