I have purchased the Just Between Us: Mother and Daughter book twice. Once when my oldest was 11 and again (same daughter) at 16. I love seeing the different answers and I love the relationship we have using this book and the memories it will serve down the line. I have one other daughter and she is 8. I was getting ready to get her the Mother/Daughter book soon too and saw this Just Between Us: Sisters online. I was thrilled. The oldest one was on board and gave it to her little sister for her birthday about a month ago. I can't tell you what an absolute gem this is. I have no idea what is in the book as the parents pinky-promised to never look, but it has done wonders for their relationship. The 8yr old is coming into her own little person and being able to talk to her big sister like this means the world to her. The older one is starting to realize her younger sister isn't as annoying as she thought and not only is she funny but she really can articulate her feelings and write. She has wanted to tell me some really cute things from the book but then stops herself. The younger one of course lights up when she see it on her pillow (they sneak it in each other's rooms) and gives the book back within a day. The older one, who is much busier with academics/sports, sometimes needs to wait a few days but I think that works better as it extends the life of the book. Highly recommend for sisters age 7 and up.