Today sees the publication of "Shakespeare's Lost Play", Double Falsehood. Theatre impresario Lewis Theobald presented the work in the 18th century as an adaptation of a play written by Shakespeare. Theobald was dismissed as a fraud, the play as a forgery. But today it appears in an Arden Shakespeare edition, finally giving it respectability as a Shakespearean work. Scholars believe the play is based on a long lost work by Shakespeare and Fletcher called Cardenio - itself based on Don Quixote. This is the latest in a line of recent re-attributions, expanding the Bard's body of work. Professor Brean Hammond and Professor Carol Rutter discuss whether there will ever be a true Complete Works of Shakespeare, and why does the canon keeps expanding?