The Norton Critical Edition is based on the 1623 First Folio text, the only authoritative edition of the play. The editor has modernized spelling but preserves, for the most part, the original lineation and characteristically heavy punctuation. The text of Measure for Measure is accompanied by a full introduction, a note on the text, textual variants, and related illustrations. “Sources” considers the probable, primary, and analogous sources Shakespeare drew upon while composing Measure for Measure, including excerpts from G. B. Giraldi Cinthio’s Hecatommithi and The Tragedy of Epitia, King James I’s Basilikon Doron, and—most directly—George Whetstone’s The History of Promos and Cassandra. “Criticism” collects seventeen important commentaries on Measure for Measure spanning four centuries, including, among others, those by Alexander Pope, Charlotte Lennox, Samuel Johnson, Elizabeth Inchbald, A. C. Bradley, G. Wilson Knight, Jonathan Dollimore, and Marliss C. Desens. “Adaptations and Responses” reprints alternative versions of the play: William D’avenant’s The Law Against Lovers (1662), Charles Gildon’s Measure of Measure, or, Beauty the Best Advocate (1700), and Charles Marowitz’s postmodern version (1975). A Selected Bibliography is also included.