Maria Blei (1867-1943), wife of the writer, publisher, and cultural mediator Franz Blei (1871-1942), who was born in Vienna, began writing a diary for their daughter Maria Eva Sibylla (1897-1962), affectionately called Billy, shortly after her birth. Enriched with three dozen photographs, it spans the years from 1897 to 1919, during which the small family lived in Zurich, Munich, Vienna, and Philadelphia, where Maria Blei studied dentistry. What started as a memoir for her daughter gradually evolved into a confessional and justificatory writing of the mother. In it, Maria Blei recorded the concerns of a modern woman willing to break free from prescribed roles. As a result, it became a valuable cultural-historical testament of the transitional period around 1900. At the same time, the diary serves as a central biographical document.