Just that, really.
My DS and DDIL and our 2-year-old DGS are about to get a pet for the first time - a (whippet) puppy a couple of months old. DGS has encountered dogs often at his other grandparents' house but not had to share his space and his parents' attention with one in his own home.
He loves books but I don't know if there's anything suitable out there to help with bonding, etc, them growing up together harmoniously, and (eventually - he's too young now) him learning to care for the dog.