Bartók's only opera, not staged until 1922, was based on a symbolist libretto written in 1911 by the future film theorist Balazs. The Duke reluctantly opens the seven doors in his castle to show his eighth wife their bloody secrets, before she joins the ghostly wives as darkness becomes total.
Not until 1964, after the trauma of Peeping Tom's reception, did Powell succeed with a musical project that is the equal of anything in his career. Bluebeard's Castle was the only opera by the Hungarian modernist Béla Bartók, written in 1911 to a libretto by the poet (and later film theorist) Béla Balazs, and widely regarded as ’unperformable' due to its lack of stage action. This Powell and Heckroth turn to advantage in an intense, expressionist psychodrama, where lighting and abstract décor convey the gradual revelation of Bluebeard's inner torment to his last wife. (...) It stands as a final proof of The Archers' and Powell's claim that the essential unity of art can best be realized in cinema.
Ian Christie (Michael Powell & Emeric Pressburger: Arrows of Desire)