The Charlie Kaufman-written, Spike Jonze-directed Adaptation is a unique semi-autobiographical fiction film. Kaufman splits himself in two, Charlie and his fictional twin brother Donald (Nicolas Cage), who pesters him while he struggles to adapt a screenplay from a novel.
Like all of David Cronenberg's work, Dead Ringers is at its core about the horror of the corporeal form. Jeremy Irons plays twin brothers, both celebrated gynecologists with polar opposite personalities who, in some strange way, need one another even in adulthood.
Denis Villeneuve's Enemy is a chilling early film from the now-famous director. Here, Jake Gyllenhaal plays a man devolving into primal obsession when he rents a film starring an actor who looks exactly like him.
David Lynch has long been fascinated by dualities, mirrors and doubles in general. Mulholland Drive is the best example of this fixation. An amnesiac in trouble and a young woman who fosters hope of being an actress find their destinies linked.
Ingmar Bergman's Persona is about emotional transmission and two becoming one.
Based on the novel of the same name by Fyodor Dostoyevsky, The Double sees Jesse Eisenberg as the one doing double duty. He plays a timid man driven nearly to his limit when another who looks exactly like him begins courting a woman he harbors feelings for.
Far and away the most whimsical instance of doubles on this list, The Parent Trap is a family classic. When twins (Lindsay Lohan) separated at birth reunite at a summer camp, they conspire to bring their parents back together.