In the arena of poetry and poetics over the past century, no idea has been more alive and contentious than the idea of form, and no aspect of form has more emphatically sponsored this marked formal concern than the line. But what, exactly, is the line? Emily Rosko and Anton Vander Zee’s anthology gives seventy original answers that lead us deeper into the world of poetry, but also far out into the world at large: its people, its politics, its ecology. The authors included here, emerging and established alike, write from a range of perspectives, in terms of both aesthetics and identity. Together, they offer a dynamic hybrid collection that captures a broad spectrum of poetic practice in the twenty-first century. Rosko and Vander Zee’s introduction offers a generous overview of conversations about the line from the Romantics forward. We come to see how the line might be an engine for ideals of progress—political, ethical, or otherwise. For some poets, the line touches upon the most fundamental questions of knowledge and existence. More than ever, the line is the radical against which even alternate and emerging poetic forms that foreground the visual or the auditory, the page or the screen, can be distinguished and understood. From the start, a singular lesson emerges: lines do not form meaning solely in their brevity or their length, in their becoming or their brokenness; lines live in and through the descriptions we give them. Indeed, the history of American poetry in the twentieth century could be told by the compounding, and often confounding, discussions of its lines. A Broken Thing both reflects upon and extends this history, charting a rich diffusion of theory and practice into the twenty-first century with the most diverse, wide-ranging and engaging set of essays to date on the line in poetry, revealing how poems work and why poetry continues to matter.