My favorite book about the Brothers Grimm is "Fairy Tales: A New History" by Ruth B. Bottigheimer.

She argues persuasively that the conventional origin normally told about the Grimm's fairy tales—-that they were recited by old peasant women remembering the ancient oral folktales of the Germanic people—-is not really true.

In fact the tales mainly came from middle class storytellers. And the two most important sources of the Grimm's tales were two Italian literary story collections from the Renaissance by Giovanni Straparola and Giambattista Basile.

It upended a lot of what I thought I knew about the origins of fairy tales.