Piano play-along. Containing eight cream-of-the-crop songs each, the books feature new engravings, with a separate vocal staff, plus guitar frames, so players and their friends can sing or strum along. The online audio files feature two tracks for each tune: a full performance for listening, and a separate backing track that lets players take the lead on keyboard. The high-quality, sound-alike accompaniments exactly match the printed music. The audio files include PLAYBACK+, a multi-functional audio player that allows you to slow down audio without changing pitch, set loop points, change keys, and pan left or right.