Averno is a small crater lake in southern Italy, regarded by the ancient Romans as the entrance to the underworld. That place gives its name to Louise Glück's tenth collection: in a landscape turned irretrievably to winter, it is a gate or passageway that invites traffic between worlds while at the same time resisting their reconciliation. Averno is an extended lamentation, its long, restless poems no less spellbinding for being without conventional resoltution or consolation, no less ravishing for being savage, grief-stricken. What Averno provides is not a map to a point of arrival or departure, but a diagram of where we are, the harrowing, enduring present.