The Continuum Companion to Twentieth Century Theatre The Cambridge companion to twentieth-century opera / The Cambridge companion to twentieth-century Irish drama / The Companion to Twentieth-Century Opera The Cambridge companion to twentieth-century English poetry / The Cambridge companion to twentieth-century Russian literature / The Oxford companion to twentieth-century literature in English The Routledge companion to nineteenth century philosophy / The Cambridge companion to the twentieth-century English novel / The Routledge companion to twenty-first century literary fiction /