Among the discerning, John Berryman is just a few steps down from the throne Robert Lowell occupies as kingpin of American poetry. With his new volume, Berryman gets even closer, for 77 Dream Songs is an extraordinary, if at times exacerbating, achievement, quite the most important collection to appear since Lowell's Life Studies and Imitations. It is extraordinary technically and thematically- it forges an idiomatic structure at once colloquial and complex, stringent and strangely supple; it anti-poetic, even eccentrically so, hard-edged lyrics, mostly three stanza sestets, evoking an embattled, preposterously pathetic splendor, a blue troubadour wandering the back rooms, back alleys of our culture. It is new and therefore difficult to describe. To talk about influences- obviously Cummings, Pound, the Beats, Michaux's ume- doesn't help either. Through most of the poems, there's someone called Henry. Henry is a Representative Type, a symbol of the American Delirium, buttressed on the one hand with minstrel medleys, on the other with classical or contemporary allusions-current events really: Ike's ""empty grin/that never lost a vote."" Frost's and Roethke's deaths etc. Henry for the most part is a figure of fun and of desperation, as much as the time after desperation. ""For the rats/have moved in, mostly,"" says Mr. Berryman, ""and this is for real."" Many will not dig the ""real"" at all; others will find the anti-bigness bizarre and ultimately boring, as at times it most definitely becomes. But beneath the ""ugly"" rhythms, the ellipsis and hurdy-gurdy ironies, an authentic voice speaks; it is urgent and upsetting. It will be around for a while.