Germany has made a Rumanian Jew the poet laureate of the Holocaust. German schoolchildren memorize Celan's ``Death Fugue,'' and politicians recite it on state occasions. Celan abjured the role and even the poem. His later work is different: edgy, spare, a stripped-down wrestling with the treacherous mother tongue. He committed suicide in 1970. Like Celan, Chalfen hails from the eastern province of the Austro-Hungarian empire, Bukovina, ceded to Rumania in 1920. Celan was born that year. The chapter on Czernowitz, his hometown, with its large, safe, prosperous community of Jews dating back to the 13th century, is fascinating. After that the book goes downhill somewhat. Chalfen sees local geography and minute events as offering a code by which to decipher obscure, and not so obscure, allusions in the poems--and he can be pretty flat-footed about it. (When Celan speaks of a swan, Chalfen inventories the region's lakes in search of the bird, overlooking an ironic allusion to the swans of one of Hîlderin's better-known poems.) Once he reaches the war years, though, his deadpan delivery is just right, a straight- on reporting of the daily horrors. The Nazis drove the Jews of Czernowitz into a ghetto, then deported them to labor camps beyond the Dniester, where Celan's parents were executed. Celan did forced labor in Moldavia. The shovels of ``Death Fugue'' were real; Chalfen refreshes the quoted poem with documented details. At war's end, the Soviets added Bukovina to the Ukraine. Celan fled to Bucharest and later to Vienna, the capital of his language. And there, in 1948, the book ends, and the enormous Celan bibliography takes over. The assiduous Chalfen hunted up over 50 people who knew Celan in his youth. He quotes them verbatim and without irony. ``An opaque subject,'' one source remarks drily of the undertaking. So it is, but in his modest, plodding way Chalfen sheds a pure and painful light on the education of a great 20th-century poet and the destroyed world that nurtured him.