A slender but important volume of nearly all the letters that passed between Nelly Sachs, a Nobel laureate in literature, and Paul Celan, one of the greatest poets of this century. Celan (19201970) and Sachs (18911970) were united by shared experiences and temperaments. Both were only children, German- speaking Jews whose lives had been shattered by the rise of Hitler. Both were poets, writing in German as a conscious act of refusal to capitulate to the Nazi terror by reclaiming the language as their own. The Rumanian-born Celan lost both his parents in the death camps and spent much of the war in forced labor; after the war he fled the wave of Communism sweeping through his country, eventually settling in Paris. Sachs was somewhat more fortunate, fleeing with her ailing mother to Sweden just before the war began. As this collection of their correspondence indicates, each was a sensitive person who bore the scars of the Nazi era with a stoicism that ultimately led to nervous breakdowns and, in Celan's case, suicide. Their 16-year-long correspondence has, as Celan biographer John Felstiner points out in his helpful introduction, ``a dynamic of [its] own: a tenderness, a certain desperate fellow-feeling of real survivorhood.'' In their letters, particularly those from Sachs following a breakdown and lengthy hospitalization, one senses the desperate fight being waged against solitude and the terrors of darkness. Often, though, another, gentler tone breaks through. A letter from Celan, written during a Brittany vacation, reveals a doting and proud father with a gentle wit. Sachs displays an almost grandmotherly attitude toward Celan's young son, Eric. The book is aided immeasurably by a set of very thorough notes and a chronology of the lives of the two poets. Poignant reading and an absolute must for anyone interested in 20th century literature or the effects of the Holocaust on those it touched.