Transitions are hard for most children, but for some, there are extra worries that no child should ever have to worry about, and books like this help educate adults working with children to ensure they are aware of the challenges of those starting with them soon and provide welcoming environments for all. It's also great to share with your child if they're going to be experiencing a transition soon too.
If you haven't got yourself a copy of this book yet, I really recommend you find it and buy a copy.