The Bach scholar Robert Marshall has argued that the sonata was composed by J. S. Bach, since it was attributed to him by two independent sources, Bach's son Carl Philipp Emanuel Bach in the manuscript copy of the work in his handwriting, and Christian Friedrich Penzel, Bach's last pupil. The musicologist Jeanne Swack has suggested alternatively that BWV 1031 was "modelled" on a previous work for flute in by Johann Joachim Quantz which survives in a version for flute and obbligato harpsichord and in another version for flute, violin, and continuo. The similarities she cites are based primarily on structural and compositional considerations, as the musical themes are clearly different.
This flawless transcription was done by the great William Thomas Best (1826 — 1897) studied at Carlisle Cathedral under John Norman and Abraham Young. Organist of the Pembroke Road Chapel, Liverpool, 1840-55; the Church for the Blind, Liverpool, 1847; the Royal Panopticon, Leicester Square, London, 1853-54; Lincoln’s Inn Chapel, 1854; St. Martin’s-in-the-Fields, Trafalgar Square, London, 1855; St. George’s Hall, Liverpool, 1855-94; Wallasey Parish Church, Birkenhead, 1860-63; Holy Trinity, Liverpool, 1863; West Derby Parish Church, 1879.
He was engaged in 1871 to give recitals at the Royal Albert Hall (stayed for only a short time), and was the solo Organist at the Handel festival at the Crystal Palace. Opened the organ in Sydney Town Hall, 1890. He was one of the greatest English Organists of his time, and received a Civil List pension of £100 per annum. Best composed church services, anthems, as well as many organ transcriptions and solo pieces.
Best was certainly the most famous British organist of the time, and was proclaimed by none other than Franz Liszt to be THE greatest virtuoso on ANY instrument!
This work can be found in Schott's "Gray Album," which features a variety of works, mostly transcriptions.
The score is attached below, as well as two photos of W. T. Best.