From the late nineteenth century through the beginning of the twentieth, the question of the relationship between unity and plurality, known as the problem of the One and the Many, occupied the minds, lectures and writings of the most eminent philosophers of both Europe and America. Poems written in dialogue forms, that is, poetry in which lines are attributed to more than one voice, inevitably recapitulate the problem of the One and the Many, because such poems must be understood both as the products of the one voice of the poet and of the multiple voices of the poem's designated speakers. Throughout the first half of the twentieth century, poets used dialogue forms extensively to explore links between aspects of the One-Many problem, including those between the individual and the world, between body and soul, and between faith and reason This dissertation examines the ways in which W. H. Auden, Thomas Hardy, T. S. Eliot, Robert Frost, and Louis MacNeice adapt traditional forms of dialogue poetry (the eclogue, dialogue of self and soul, ballad, and drama) to their discussions of aspects of the question of the One and the Many. These poets manipulate the three distances inherent in dialogue poetry---the distance between the speakers, the distance between the poet and the speakers, and the distance between the speakers and the reader---to reconcile form and content to the extent that the forms of the resulting works reflect each poet's understanding of the nature of unity and of the relationship between the One and the Many as expressed within each poem