Diamante's Reina María Estuarda traces the tragic misfortunes of Mary Queen of Scots from her arrival in England until her death. The value of the present edition is not only the availability of this inaccessible play in a readable format, but also its efforts to rehabilitate Diamante, to demonstrate the value of this comedia and to enable the Hispanist to consult the writings of one of Calderón's significant contemporaries.