Fill yourself with Regan's imaginative spirit and make yourself a friend this fall with this children's book on sharing. Perfect for fans of Rulers of the Playground! This is MY Castle by Brooke Van Sickle and Gabriela Dieppa is a heartfelt, children's friendship book about Regan who finds the most amazing, perfect castle in the world but there's a problem -- it's already taken. Now she must decide: claim the castle herself or share it with an invader.