12 Children's Pieces (12 Pièces Enfantines, Op.31) by Reinhold Gliere is a collection of medium-difficulty pieces written for young pianists. Contents: Prélude; Nocturne; Berceuse; Rêverie; Chanson populaire; Valse; Romance; Etude; Mazurka; Chant oriental; Feuillet d'album; Air de Ballet.