By October 1936, Victor Klemperer, a Jew, had been removed from his professorship at the Technical University in Dresden, Germany. He and his ''Aryan'' wife, Eva, lived in a small house of their own in a rural suburb of Dresden. They were ''virtually destitute,'' Klemperer notes in ''I Will Bear Witness,'' his diary of the years from 1933 to 1941. (A second volume, to 1945, will be published next year. Klemperer died in Dresden in 1960.)

In hopes of finding an appointment abroad, Klemperer had begun writing letters to friends and scholars all around the world, but it was already too late, as he well knew, and he considered himself bound to Germany. The house and its garden were the chief adornments of Eva's life, and, as Klemperer later said of his marriage, ''I have always seemed glorious to myself on this one point of love and faithfulness.'' Eva, who shared all of her husband's privations, might have said the same.

No single metaphor can convey the oppressive reality of living in a world that becomes, without limits, steadily more menacing and constricted. Every day Klemperer weighed his wife's infirmities, which were many. Every day he retallied the dwindling supply of marks and pfennigs and reassessed the restrictions the Nazis had imposed -- the loss of library privileges and the right to buy tobacco and to drive a car and to live in one's own home and, eventually, to move about the streets without wearing a yellow star. Yet every day, with few exceptions, Klemperer wrote in his diary and worked on a scholarly study of 18th-century literature. It was a labor not of desperate distraction but of love.

Something about Klemperer makes him the most extraordinary German witness of Nazism that has yet come to light. Reviewers have mentioned his literary skill and his determination to chronicle the details that the historical record would miss -- details that he, a Jew cast away in a sea of anti-Semitism, read as auguries of his fate. These are great qualities indeed, but what illuminates them is his faith in reason.