"It consists of poems (or "glosses" as Heaney terms them) based on the figure of Sweeney from "Sweeney Astray" (1983), Heaney's translation of the medieval Irish text "Buile Suibhne".In his introduction to "Sweeney Astray" Heaney indicates the significance that the story of Sweeney has for him by writing that it can be seen as "an aspect of the quarrel between free creative imagination and the constraints of religious, political, and domestic obligation."