Book excerpt: What is the relationship between poetry and power? Should poetry be considered a mode of authority or an impotent medium? And why is it that the modern poets most commonly regarded as authoritative are precisely those whose works wrestle with a sense of artistic inadequacy? Such questions lie at the heart of Shades of Authority, prompting fresh insights into three of the most important poets of recent decades: Robert Lowell, Geoffrey Hill, and Seamus Heaney. Through attentive close readings, James shows how their responsiveness to matters of political and cultural import lends weight to the idea of poetry as authoritative utterance—but also how each is exercised by a sense of the limitations and liabilities of language itself.