Elizabeth Jane Coatsworth was best known as the author of Away Goes Sally, The Cat Who Went to Heaven, which won the 1931 Newbery Medal, and the four Incredible Tales, but in fact she wrote more than 90 books for children. She was extremely interested in the world around her, particularly the people of Maine, as well as the houses and the surrounding land. She also loved the history and myths of her favorite places, those near her home and those encountered on her countless travels.
Coatsworth graduated from Vassar College in 1915 and received a Master of Arts from Columbia University in 1916. In 1929, she married writer Henry Beston, with whom she had two children. When she was in her thirties, her first books of adult poetry were published. For over fifty years, she continued to write and publish poetry in collections and to weave poems between the chapters of her books of fiction.
Prefacing your collection of short tales with a frame narrative of someone finding a manuscript where the stories are so amazingly good that they have a literally magical effect on the hearer is setting the bar really high for yourself. Just something to keep in mind, authors.
These stories were not all that. They are pretty flat, sentimental, and typical of the didactic tradition in children's literature that reinforces social norms and traditional filiality. Children are dutiful and hard-working. They suffer in silence and without resentment, even if they are essentially slaves, having been sold by impoverish parents to a master. They accept the caste system and their laces in society. Girls are pretty and quiet, boys are brave and aggressive. Everyone loves the government.
There are no notes, so I have no idea if Coatsworth made these up entirely or based them on something. One story features a prince who slays an evil dragon, which doesn't sound like something that would happen in Japanese mythology (dragons are mostly positive, and water-dwelling) but I guess it could have been a nure-onna or some other monster, and the author switched to a more familiar term.