'Six Pieces' Op. 19 is the first collection of piano pieces by Tchaikovsky which contributed significantly to his growing renown as most important Russian composer apart from Anton Rubinstein. Famous contemporary pianists likeNikolai Rubinstein and Hans von B&uuml,low performed R&ecirc,verie du soir (Op. 19, No. 1) or Th&egrave,me original et variations (No. 6) in their concerts in the 1870s. Commissioned by his Moscow publisher P. I. Jurgenson, SixPieces Op. 19 was composed by Tchaikovsky in the summer and autumn of 1873, i. e. during his time as professor of theory at the Moscow Conservatoire. B&uuml,low had entered 'little changes' in his own copy of the first editionofVariations Op. 19/6. There is, however, no documentary proof which of B&uuml,low 's changes Tchaikovsky eventually included in the Nouvelle &eacute,dition revue et corrig&eacute,e par l&rsquo,auteur of Op. 19 published only in1890. The present new edition therefore contains both versions of the Variations. Tchaiko vsky 's version of the first edition can be found in the appendix of the present volume, B&uuml,low 's version expressly adopted by Tchaikovskyis presented together with Nos. 1 -5 in the main text of the volume on the basis of the Nouvelle &eacute,dition revue et corrig&eacute,e par l&rsquo,auteur from 1890.