This book examines the influence of American poetry on Seamus Heaney's achievement by close attention to the themes, style, and resonances of his poetry at different stages of his career, including his appointments in Berkeley and Harvard. Beginning with an examination of Heaney's education at Queen's University, this study presents comparative close readings which explore the influence of five American poets he read during this period: Robert Frost, John Crowe Ransom, Theodore Roethke, Robert Lowell, and Elizabeth Bishop. Laverty demonstrates how Heaney returned to several of these poets in response to difficulty and to consolidate later aesthetic developments. Heaney's ambivalent critical treatment of Sylvia Plath is investigated, as is his partial misreading of Bishop, who is understood today more sensitively than in her lifetime. This study also probes the reasons for his elision of other prominent American writers, making this the first comprehensive assessment of American influence on Heaney's poetry.