the book the father was writing - Fathers and Daughters

I found myself wondering what the book was about that the father (Russell Crowe) was writing - the Fathers and Daughters book. It was implied that it was inspired by him and his daughter, but I didn't find their life as depicted all that inspiring. They showed us that he was working (writing) all of the time. She was in school all day and otherwise we didn't see her having friends or even a pet. I'm just curious what that story was about, that it was such a huge success and became Aaron Paul's favorite book ever.