2003 Honor book
"Hattie Owen has never really thought about the world outside her small town. Her family's boarding house is where she feels most at home, with its eccentric tenants and predictable routines. But there are secrets in Hattie's family, and the biggest one is her young uncle Adam. Hattie doesn't even know he exists until he shows up in her town, right when she's about to turn twelve. Suddenly the place she thought she knew so well begins to feel different. Her family and neighbors aren't ready to deal with Adam's mental problems...so Hattie gets caught in the middle. In one summer, Hattie will find out how small a small town can be, how big the world outside is, and how far our hearts and minds can go."
Ann M. Martin has been one of my favorite authors since I was about 11 years old, and discovered the Babysitter's Club series. I really enjoyed this book. The relationship between Adam and Hattie was heartwarming. It had developments that made the book very gripping (but I'm not going to give anything away...)
It is interesting to me just how many award winning books deal with the topic of autism.