Imre Mez (born 1932) composed several popular works for children and young people studying music. His most recent collection is extraordinary in that all the 153 tiny pieces are based on the same Hungarian folk song, offering a myriad of ways and options of presenting and elaborating the same melody without altering it.

The variations are grouped by key and, within each chapter, are placed in order of difficulty. In so doing, the composer offers, as piano teacher Erika Becht writes, ''two wa...