Jill Matus uses bio-medical, social scientific and literary texts to interrogate Victorian concepts of sexual difference. Departing from the usual critical focus on Victorian conceptions of the sexes as incommensurably different, she emphasises the powerful effects in Victorian culture of notions of sexual instability and approximation. While ideas about mutable or ambiguous sexuality provoked fear and fascination, they also served Victorian middle-class ideology by offering 'scientific' ways of constructing racial, class and national identity in terms of the body. Throughout this period fierce public debates raged around prostitution, infanticide, working-class sexuality, female reproduction and domesticity. Drawing on works by Elizabeth Gaskell, George Eliot and the Brontes, Matus explores the dialogue between literary and other discourses of sexuality. Unstable bodies will be an essential reference work for students and scholars working in Victorian literary and cultural studies, feminist studies, and the history of sexuality.