Shards of memories—dreams of an individual, collective nightmares—do not merely haunt Andrei Tarkovsky’s most challenging work, they are the film, which invents, as Ingmar Bergman noted, “a new language, true to the nature of film . . . life as a dream.” Ostensibly an autobiographical portrait, Mirror also offers a crash course in twentieth-century history, as stock footage of world upheavals intertwine with images of childhood: a field, a fire in a rainstorm, a father’s voice, a mother. “Words cannot express a person’s emotions; they are too inert,” insists a poem written and read by Tarkovsky’s father. Tarkovsky’s art, however, does just that.