Gustaf Tenggren was one of the masters of the early days of picture books. He set a standard we still work by today. He was also one heck of a marketer. He started out with Disney but quickly realized it did him no good to sign his work 'Disney.' Hence, the Tenggren books and the golden days of the Golden Books.
Did you have a "Tenggren Tell-It-Again Book" when you were a kid? Do you recognize the style? Go to AnimationArchive.org for a fantastic summation of Tenggren's work at Gustaf Tenggren and the Genesis of the Golden Book Style.