No one has satisfactorily explained how it is that a whole young generation of Irish poets—Heaney, Mahon, Longley, Muldoon and others—is apparently devoted to the well-made poem at a time when their English, Scottish and to a smaller degree Welsh contemporaries have almost entirely thrown it overboard in favour either of grim fragments or of vapid maunderings. The longest poem in Derek Mahon's [Lives], "Beyond Howth Head", is of a shapely fluency which set the pattern for the verseletters of Seamus Heaney and Michael Longley: behind it all there is perhaps the shadow of the Robert Lowell of "Near the Ocean" and "Waking Early Sunday Morning". Whatever the explanation, these new poems of Mr Mahon's have an attractive suppleness and wit. What stops them from going beyond that is a common quality of being marginalia, literary notes ("An Image from Beckett", "J. P. Donleavy's Dublin", "After...