In 1739, Scarlatti's early keyboard sonatas were published by Cooke in London as a two-volume collection of sonatas titled "XLII Suites de Pieces Pour le CLAVECIN" (42 Suites of Pieces for the Harpsichord). This was a pirated edition by the composer's friend, Thomas Roseingrave, and starting with this edition, Scarlatti's works continued to be published in the 18th century in scores of low authenticity. Roseingrave, citing the wishes of subscribers, inserted his own introductory piece, "Introduction," at the beginning of the collection and a fugue by Alessandro Scarlatti in the middle of the collection. The cover stated that the publisher itself had corrected errors in previously published scores. This collection includes the 30 pieces from the Essercizi, an alternative version of K. 8, and K. 31-42, making it the most important primary source for K. 31-42 today.

K. 31 Allegro 2/4-Adagio 3/4-Allegro 2/4 g-moll

Overall, the formal divisions are clear, and changes in the musical character are also distinct, such as the opening section with weighty chords and the alternation of single melodies between the hands. While preceding and succeeding sections are strongly contrasted in this way, the music sounds as if it flows smoothly, for example, due to the overlap of the end and beginning of adjacent phrases at texture changes (e.g., m. 12). The second half begins with the opening phrase of the movement, and after a four-measure sequence based on new material from m. 57, the transitional section from the first half (m. 11~) reappears. In the Andante, although the motion is simple, attention must be paid to changes in meter and differences in note values between the hands. The corresponding passage in the second half does not involve a meter change and becomes a two-measure sequence.