"Persona" has been subject to a variety of interpretations. According to Professor Thomas Elsaesser, the film "has been for film critics and scholars what climbing Everest is for mountaineers: the ultimate professional challenge. Besides "Citizen Kane", it is probably the most written-about film in the canon". Critic Peter Cowie wrote, "Everything one says about "Persona" may be contradicted; the opposite will also be true". Academic Frank Gado called Cowie's assessment "patent nonsense", but agreed there was "critical disarray"; editor Lloyd Michaels said that although Cowie exaggerated somewhat, he welcomed the "critical licence" to study the film.