A cycle of unrhymed sonnets dealing with public and private crises, marriage, middle age, and fatherhood, Notebook 1967–68 is considered by many readers to be one of Robert Lowell’s most innovative and searching works. Yet these freeform sonnets (which Lowell reworked in later volumes) are not included in their original form in his Collected Poems. Praised by Seamus Heaney for its “immediate, unprepossessing, blunt-edged force,” Notebook 1967–68 is a key to Lowell’s later style and a landmark in twentieth-century poetry.