"The works in this book will stand alone as piano solos, but they should be performed as duets, using the backup tracks included on this CD. There are two tracks included for each work. The first track includes the piano solo, so the performer can hear how the duets work and when the piano solo enters. The second track is the performance track, without the piano solo. The backup track introduction is also shown in small notes at the beginning of each score, to clarify the performer's entrance. These small notes are not played by the performer."