Published in 1983, Sweeney Astray is Seamus Heaney’s version of the medieval Irish work Buile Suibhne. Its hero, Mad Sweeney, undergoes a series of purgatorial adventures after he is cursed at the Battle of Moira. The poetry spoken by the mad king, exiled to the trees and the slopes, is among the richest and most immediately appealing in the whole canon of Old Irish literature and this translation not only restored a work of historical and literary importance, but allowed Heaney’s voice to reinforce its claims on the reader of contemporary literature.