Book excerpt: The cultural fantasy of twins imagines them as physically and behaviorally identical. Media portrayals consistently offer the spectacle of twins who share an insular closeness and perform a supposed alikeness--standing side by side, speaking and acting in unison. Treating twinship as a cultural phenomenon, this first comprehensive study of twins in American literature and popular culture examines the historical narrative--within the discourses of experimentation, aberrance and eugenics--and how it has shaped their representations in the 20th and 21st centuries.