As a man who disclaimed any kind of religious orthodoxy, Robert Penn Warren nonetheless found in Christianity "the deepest and widest metaphor for life." The significance he drew from it was one he expressed strictly in humanistic and natural terms: spiritual renewal and redemption were possible through engagement with literature and participation in the world. In Robert Penn Warren's Modernist Spirituality, Robert Koppelman explores the spiritual or religious dimension to Warren's work in light of his admitted agnosticism.

Beginning with an overview of Warren's career as a Fugitive at Vanderbilt and then, later, as a formidable New Critic, Koppelman argues that Warren's regard for the spiritual aesthetic of both literary language and form can be traced to his early study of poetic metaphor. To illustrate Warren's mature vision, Koppelman centers his study on two novels and two poetry collections: All the King's Men, A Place to Come To, Promises: Poems 1954-1956, and Now and Then: Poems 1976-1978. He also examines the critical studies that concentrate on Warren's vision of time, history, and spiritual fulfillment, as well as those essays by Warren that complement his poems and novels in such a way as to elicit the reader's participation in the redemption of their narrators.

Robert Penn Warren's Modernist Spirituality renews Warren's commitment to experiencing both literature and life as opportunities to participate in a realm of beauty and vision that is still open to contemporary readers.