"A Young Girl's Diary" is a book by Sigmund Freud that was published in 1915. It is a collection of diary entries written by a young girl named Anna between the ages of 11 and 14. The diary was given to Freud by one of his patients, who was also Anna's father. In the diary, Anna writes about her daily life, her relationships with her family and friends and her experiences as a growing adolescent. Freud uses Anna's diary as a basis for his psychoanalytic theories, particularly his theories on female psychosexual development. The book is significant because it provides a rare glimpse into the inner thoughts and experiences of a young girl during a time when female voices were often silenced. It also sheds light on Freud's theories and his approach to psychoanalysis. However, the book has also been criticized for its invasion of Anna's privacy and its potential exploitation of her experiences.