The Duo Concertant, opus 55, for two ®bass trombonesŻ (the German designation at the time; but in fact for two tenor-bass trombones, i.e. large bore Bb) was published in Paris by Richault, at Boulevard PoissonniŠre (price seven francs fifty). From this address we know the work appeared before 1841, since that was when the publishing house of Richault moved to new premises. Belcke enjoyed a high reputation in French musical circles. His name was used by the publisher Richault, for promotional purposes, beside that of Vobaron (Methode de Trombone by V. Cornette; 1831 edition). A later edition "for two bass trombonnes [sic] or two bassoons" was published by Breitkopf und H„rtel in 1834, and was distributed in France by Maurice Schlesinger, price two francs fifty (Revue et Gazette musicale de Paris No. 38, 21 September ). The Duo Concertant, in three movements, with extensive development, is a work that makes considerable technical demands on both players. The original score is in the bass clef; we have sometimes used the tenor clef for ease of reading. Additions are shown in square brackets, (accidentals in round brackets). Though originally published as separate parts, both have been brought together for this edition. -Raymond Lapie