[French Composers] [Lefébure-Wély, Louis James Alfred. (1817-1869)]Meyerbeer, Thomas, Halevy, Auber, Alart, Herz, Marmontel, Carafa, Reber, Meissonier, Massart etc. Signed Endorsement for Lefébure-Wély's "L'école concertante de piano."An extraordinary document, a signed letter from the professors of the Conservatoire Imprial de Musique endorsing the keyboard method of the important French organist and composer who played a central role in the development of the French symphonic organ style. 1 page, 33 x 21 cm.. Ca. 1855, describing the method in detail, and signed in full below by many leading composers and musicians of the period, including Giacomo Meyerbeer, Adolphe Adam,