Book excerpt: A vital hub of poetry readings, performance, publications and radical politics in 1960s New York, the Umbra Workshop was a cornerstone of the African American avant-garde. Bringing together new archival research and detailed close readings of poetry, A Black Arts Poetry Machine is a groundbreaking study of this important but neglected group of poets. David Grundy explores the work of such poets as Amiri Baraka, Lorenzo Thomas and Calvin Hernton and how their innovative poetic forms engaged with radical political responses to state violence and urban insurrection. Through this examination, the book highlights the continuing relevance of the work of the Umbra Workshop today and is essential reading for anyone interested in 20th-century American poetry.