Letter from an Unknown Woman is a novella by Stefan Zweig. Published in 1922 it tells the story of an author who while reading a letter written by a woman he does not remember gets glimpses into her life story.
A rich and well-known writer (R.) returning home to Vienna from one of many holidays finds a long letter from an unknown woman (Fräulein). As a teenager the woman had lived with her poor widowed mother in the same building and had fallen totally in love with both the opulent cultured lifestyle of her neighbour and the handsome charming man himself. Her passion for the writer was not lessened by the flow of attractive women spending the night with him nor when she had to leave Vienna and moved to Innsbruck when her mother remarried. At age 18 she returned to Vienna took a job and tried to meet the writer again. He did not recognise her and without revealing her name she succeeded in spending three nights with him before he disappeared on a long holiday.