This critical edition of all the sonatas of Domenico Scarlatti is justified by the necessity of offering performers and scholars a text which is philologically faithful to the author's intentions (in so far as this can be reconstructed through a comparative study of the surviving printed and manuscript sources) and which is presented as authentically as possible, free from editorial interference or suggestions for performance or interpretation. The study of musicology and especially of the performing traditions of baroque music has advanced considerably since Alessandro Longo achieved the mammoth task of publishing the entire corpus of Scarlatti's sonatas for the first time, and today we can deal with problems of text and interpretation with a surer and deeper methodological awareness; all of these will be adequately treated in the Appendix to this edition, which will contain also a general thematic catalog of the complete sonatas.