I read this so that I could know the fairy tale behind another book called Tam Lin by Pamela Dean. Yolen does a great job of re-telling this ballad as a kids' story. She also puts a version of the original ballad at the end of the story and gives a brief history of it. Excellent!!
I love everything by Jane Yolen, so this is no exception. Lavishly illustrated to go with the folk tale.