When Marnie Was There

I really love this book because it is about a lonely girl who learns to make friends and overcome her struggles. Inside this book is the following description: "Brooding, lonely Anna, a foster-child, goes to stay with a kind Norfolk couple. There, like something in her memory, she finds the old house backing on to the creek. But it is the girl at the window who haunts her ... Marnie, headstrong, often infuriating and somehow just as elusive when the two meet as she had been at the window. Marnie becomes Anna's perfect friend, and although she finally vanishes for good, she has helped Anna make real friends. "This is a thrilling, intense story, part mystery, part adventure, part fantasy, and will appeal particularly to girls of eleven and upward."