Do you know of any children's books that teach kids not to bully other kids? Or books that teach the value of kindness? Thanks!

When I was a kid, The Berenstein Bears series were my favourites and they have lots of good messages for kids. This particular book about bullying is particularly good because after his sister was bullied, the brother decided to take things into his own hands only to realize that his sister's bully is a little girl too and learns to resolve matters with kindness and friendship. Highly recommended!