The only previous attempt to collect Kyd's writings was made by Frederick S. Boas, a well-known historian of early modern drama. Boas included three authentic works: The Spanish Tragedy, Cornelia, and The Householder's Philosophy. Boas rightly included Soliman and Perseda, urging its acceptance as genuine (pp. liv–lxi); this was just before Charles Crawford published his definitive attribution (1903). Boas was less judicious when he included the undistinguished prose pamphlet, The Murder of John Brewen (1592), which has no resemblance to Kyd. Boas accepted J. P. Collier's attribution on the basis of a signature, ‘Tho. Kydd’, in one copy: it has since been shown that this was another Collier forgery. Boas forcefully rejected The First Part of Ieronimo as spurious (pp. xxix–xliv), but then printed it not as an appendix but in the text (pp. 295–337). Boas had followed up Sidney Lee's discovery of Kyd's first Letter to Puckering, and included a facsimile and a transcript. In an appendix, he included Kyd's Verses of Praise and Joy (pp. 339–42), but unkindly dismissed them as ‘a specimen of Kyd's non-dramatic hack work’ (p. xxv). Boas briefly discussed Arden of Faversham, finding it

There are sensitive and perceptive comments in Boas's introduction, but the main weakness of his edition is its careless treatment of Kyd's text. The long critical review by W. W. Greg exposed an embarrassing number of errors.

Kyd has been much more fortunate in editions of single works, such as the ‘Revels Plays’ editions of The Spanish Tragedy by Philip Edwards (1957) and of Arden of Faversham by M. L. Wine (1973), and the comparable edition of The Spanish Tragedy by Clara Calvo and Jesús Tronch (2013) for ‘Arden Early Modern Drama’. While we acknowledge what we have learned from those editions, our aims are different. The priorities of this Collected Works are to provide textually accurate modern spelling versions, freshly derived from the original quarto editions, with full commentaries.