James Shirley's The Dukes Mistris was licensed in 1636 and published in 1638. The play has not previously been edited in accordance with modern bibliographical standards; the only available text outside copies of the original Quarto is the modernised edition prepared by William Gi'fford and Alexander Dyce for The Dramatic Works and Poems of 1833. This edition aims to revive critical and dramatic interest in the play itself while establishing a text which will provide a sound basis for scholars and students of Renaissance drama alike. My edition is based on a collation of twenty copies of the 1638 Quarto (at least six of each of the three variant states which exist). All variant readings deriving from press correction are recorded. The original spelling has been retained and punctuation is emended sparingly. All emendations are included in the textual footnotes, and substantive emendations are discussed in the commentary. The commentary includes interpretive comments, glosses, textual notes, dramatic analogues and explanation of contemporary references. The Dukes Mistris, a tragicomedy, was written during a period when Charles I was ruling without Parliament and when prlciosite was flourishing at court. One of the most significant aspects of the play, I believe, is its relevance to the contemporary political and social situation.' The introduction to the edition discusses in some detail the thematic concerns of the play and their context: love and service, the royal prerogative and Platonic love. While the ideas of the play add considerable interest, they are set in a chain of love entanglements which are conventional in tragicomedy. Shirley's dramatic craftsmanship is approached from the perspective of tragicomedy and its conventions since the language, characterisation and structure of the play reflect his skilful blending of tragic and comic modes. The Dukes Mistris makes no profound statements but it is successful tragicomedy and effective theatre. In play-text, introduction and commentary, the staging of the play receives consideration in the hope that this edition will encourage production on the modern stage.