This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book investigates the extent to which the operas offer a critical revaluation of the original authors by celebrating these lesser works. It explores the literary implications to both source and librettist when prominent writers adapt what at the time would have been seen as relatively obscure works of literature. The book examines specific operas in order to isolate and address questions about the libretto's literary status and aspirations, and the relative role of music and literature in the creation of opera. The use of medieval narratives in modern British opera ostensibly allows for a staged awareness of national culture and 'modernity'. It brings together this interest in the adaptability of particular sources and genres with a renewed consideration of tensions between composer and librettist, and librettist and literary source.