Keira Knightley is brilliant as a temporarily insane woman who has an affair with her psychiatrist—and that psychiatrist just happens to be Carl Jung (masterfully played by Michael Fassbender). Viggo Mortensen does an impressive turn as Sigmund Freud in this spellbinder from director David Cronenberg. Knightley delivers one of those high-wire performances that go right to the edge of physical and emotional cohesion. When her character is “ill” in the film’s early stages, her tics and fits are so real that I was actually concerned for her. Watching Fassbender’s Jung and Mortensen’s Freud having intellectual battles over sex and the psyche is a great acting feat. This is the best thing Knightley has ever done.