Heaney dug into the bog and found the preserved bodies of Iron Age sacrifices, and from them made poems about violence, history, and Ireland's Troubles. The collection established him as more than a pastoral poet; the beauty is earned against terror. The bog poems are archaeological and mythological at once, finding in ancient ritual murder a way to approach contemporary sectarian killing. Heaney's language is dense with consonants, tactile and dark. He would win the Nobel Prize twenty years later, but this book announced his full powers. The past rises from the bog. It has something to tell us.