These were composed during the middle of Rachmaninoff's career, and created a foundation of inner voices that he would elaborate on in his Preludes (Op. 23) and Études-Tableaux (Op. 33).
Estas pezas foron compostas cara á metade da carreira de Rachmaninov e creou unha base de voces centrais que elaboraría nos seus Preludios, Op. 23 e Études Tableaux, Op. 33.