There are four volumes of Balzac's letters: two volumes of miscellaneous letters known as the Correspondance and two very substantial octave volumes containing the master's messages to Madame Hanska during the seventeen years they were engaged. The latter collection has been poetically entitled Lettres à l'Etrangère. All four volumes have always been considered a rich store of biographical information. The Correspondance has been twice edited: in the two-volume edition published by Calmann-Lévy in 1877, and in an octave volume which forms part of what is known as the édition définitive of the Œuvres Complètes (Calmann-Lévy, 1876). The Lettres à l'Etrangère were published by Calmann-Lévy in 1906. None of these volumes contains information as to its editors or their method of procedure.