In this book David Aers examines Christian literature, theology and culture in the late medieval period and especially debates over orthodoxy. By studying a range of texts including Piers Plowman, and those by John Wyclif, William Langland and Walter Brut, he asks why some were considered orthodox and others heretical. Throughout he looks at theology and doctrine in processes of continuity and reform in the Church and discusses how Christians and the Church drew on existing Christian traditions when faced with the issues of the 14th and 15th century.