I really liked this book of short stories of the friendship between Frog and Toad. This book really focuses on what it means to be a friend and what you can do when you have a friend that's having a difficult time. The artwork is super sweet, too, and I think the morals laid out throughout the stories are good for children to learn.
If you have a little or are curious yourself, please give this a read. It's short, it's sweet, and it has good moral lessons. I recommend it!