My head tells me this is the greatest film ever made; these days, my heart isn't far off agreeing. Bergman's most brazenly experimental work has since settled into something, if far from typical, then somewhat defining – with its breathtakingly severe two-tone imagery and boldly sliced narrative merging two characters and actresses into one silvery, amorphous concept, “Persona” represents a kind of supremely confident shorthand for all the director's troubled, troubling preoccupations with identity, spirituality and the camera. “What is the film actually about?” I remember a hapless student once asking at a lecture. “What isn't it about?” the lecturer snipped back – an idle answer, certainly, but not altogether the wrong one.