Robert Duncan’s writing played a central role in translating the impetus of poetic Modernism into the forms that proliferated during the last half of the 20th Century. This dissertation gives a comprehensive account of the pivotal moment in Duncan’s career, when he forged the new poetics that would unfold in his central works. Drawing on a trove of archival materials, this study reconstructs Duncan’s reckoning with the limits of Modernism and Romanticism, especially in his reading of Pound, Stein, and Blake; and, in an analysis of the drafts of “Often I Am Permitted to Return to a Meadow,” it details how he discovered his new way. This poetics was formed of two contrasting ideas, the “open field” and “the structure of rime.” The body of the dissertation shows the decisive role that Duncan’s reading of the Zohar played in the formulation of these ideas, while the last part explores how Duncan extended his new concept of poetry. A chapter on “A Poem Beginning with a Line by Pindar” shows how this poem systematically articulates the expressive range of language, from babble to the periodic sentence, from verse to prose. It discusses this poem’s debt to Duncan’s reading of Charles Williams’ novel The Greater Trumps and of Dante’s “Letter to Can Grande.” A second chapter addresses Duncan’s response to the Vietnam War. It gives an account of his special idea of America as “the nation of nations,” and of the contributions of Whitman, Dante, and Ernst Kantorowicz to Duncan’s thought. The dissertation proposes a “method,” which is unusual in the study of contemporary poetry, simply, integrating textual history and philological analysis into a) the critical interpretation of specific texts and b) the exposition of the ideas of poetry (the “poetics”) enacted by the poet’s work. Thus, it grounds the radical poetic and political positions, which have been attributed to Duncan, in specific acts of language. It attempts to give a rigorous account of how poetic form might bring to life another “sense of reality.”