I enjoyed this book, though I didn't like the format. It was hard to follow who was writing, whether it was a letter from a friend of the family, Olga, or her father. It was also unclear why some entries would be left out or if it was the complete thing.
That said, I thought the author did a great job summarizing what was happening and humanizing Olga. I would have been on board with a little speculation as well to what she did day to day, but as a historical document, I understand the importance of objectivity.