""Must form itself become the work of anguish?"" Sacks's fourth collection of poetry argues that indeed it must. Compression, elision, and tense lexical compounding are the devices Sacks, following if not equaling Mandelstam and Celan, selects for this work of proleptic mourning--for a father in the excruciating final stages of a disease that leaves him, like the Marsyas of Greek myth, ""flayed by Apollo,"" and for a South Africa shedding the skin of apartheid in convulsions that bring ""the wild speeding up of change to absolute."" The poet means us to hear the death-rattle of impending retribution in the latter phrase and elsewhere; the poem ""Relief,"" for one, ends abruptly on the words: ""Waiting to be killed."" The odd-numbered sequences of the five-section book engage fragmented forms of lyric utterance (one notes the debt to Jorie Graham) to sound an ominous landscape, similar to the actual combat zones Sacks recalled in Natal Command: ""I felt it/ in the warning/ downward// leaf & branch/ beneath// their fingers/ rapid// murderous/ (& there was music // --hacking)."" These alternate with sections charting--with dire, if chronically oblique, precision--the nightmarish vicissitudes of terminal illness. Though his command of the elegiac register is subtle and studied (he devoted a scholarly monograph to the subject in the mid-1980s), Sacks is a less adept political allegorist: the three sections of wide-scope meditation are prone to phobic and dystopic stereotypes as the disoriented poet grasps at myth and mystique to make sense of South Africa's complex social transformation. Even so, the personal and political anguish of this volume is hard to gainsay. Imagining the knife blade pressed to his neck, Sacks does what he must: ""sing out, the blade says,/ sing.""