A figure from ancient folklore, the doppelganger-in fiction a character's sinister look-alike-continues to reemerge in literature, television and film. The modern-day doppelganger ("double-goer" in German) is typically depicted in a traditional form adapted to reflect present-day social anxieties. Focusing on a broad range of narratives, the author explores 21st century representations in novels (Audrey Niffenegger's Her Fearful Symmetry, Jose Saramago's The Double), TV shows (Orphan Black, Battlestar Galactica, Ringer) and movies (The Island, The Prestige, Oblivion).