Then one day I received his telegram, which was like an operalibretto, just as theatrical, as dangerously childish and false, as everything he had said and written to others twenty years before .
It consists of poetry (often the briefest of fragments), a selection of essays, including several about authors from classical antiquity, and even the libretto of an opera.
So I don't think it was unusual for Bartok to pick a revisionist rendition of a dark and terror-filled fairy tale as the libretto for his first and only opera, Duke Bluebeard's Castle.