In Book 4, we welcome contributions by Martín Cuéllar (a lyrical etude), David Karp (a Halloween piece and an equal-part duet), and Kevin Costley (an arrangement of America the Beautiful), along with showpieces by Melody Bober and Kevin Olson, who has also arranged a classical theme solo of Offenbach's Barcarolle. New elements include: sixteenth note patterns, compound meters, inversions of I, IV, and V chords, octave scale passages, some LH melodic passages, and more intricate accompaniments.