NONFICTION : AT THE HEART OF THE WHITE ROSE: LETTERS AND DIARIES OF HANS AND SOPHIE SCHOLL, edited by Inge Jens; translated from the German by J. Maxwell Brownjohn (Harper & Row: $18.95; 336 pp., illustrated).

These tormented, poetic letters and diaries are fragments that leave much unsaid and depend greatly on the editor’s exposition. For anyone still bewitched by World War II, they make engrossing reading. They begin in 1937 and end abruptly in 1943, when the two writers were guillotined in Munich for distributing leaflets that accused Hitler of “ . . . leading the German people into the abyss.”

These Aryan martyrs are Sophie Scholl, a kindergarten teacher, and her beloved brother Hans, a medical student, executed at 21 and 24. Hans became the leader of a handful of students who formed the anti-Nazi resistance group known as the White Rose.

From the first, their writings portray intense, cultured young Germans, already at odds with National Socialism, who nonetheless serve Hitler when ordered. They describe their travels, discuss religion and books with fervor. As Hans waxes, (March 3, 1938): “My whole body, every sinew, every vein of it yearns for life.” Life, alas, was not to be his fate. Hans writes (June 11, 1940): “I don’t know how much longer I can bear to watch this butchery of ours.” And Sophie (Oct. 6, 1939) has already dreamed of a heavy iron ring around her neck.

The question of why so few resisted Hitler remains unanswered. But, for those brave few who did, it is at the foot of their graves, rather than at Bitburg, that Reagan should have laid his wreath.