In his early compositions, Bartók composed many piano pieces based on folk material. However, after composing the orchestral work Dance Suite in 1923, he suspended his creative activities for three years. Following this preparatory period, in 1926, Bartók demonstrated his intention to enter his “late period” with a style entirely different from his early works.

Many important works were created in this year, and among them, the Piano Sonata, which marked the beginning of these compositions, is the most significant among his piano solo works. It is Bartók's only piano sonata and the largest in scale among his solo piano compositions. Stylistically, it combines the folk characteristics seen in his early works with an added layer of abstraction, pointing towards a world of absolute music.

Musically, it exhibits a sophisticated compositional technique, characterized by highly percussive and diverse rhythms, short melodies, percussive attacks with dense chords, wide dynamic contrasts, contrasting timbral arrangements, and a robust formal structure.

First Movement: Allegro moderato

It is predominantly based on the pitch E, which is particularly emphasized at the beginning and in the concluding section. It is filled with vibrant energy and sonority. This movement precisely combines a light first theme, a quiet second theme, and diverse rhythms derived from them.

Second Movement: Sostenuto e pesante

In contrast to the preceding and following movements, it possesses a heavy yet tension-filled atmosphere.

Third Movement: Allegro molto

The finale has a particularly strong folk dance character. It takes a modified rondo form. The themes are simple and clear. It features frequent meter changes, possesses a modern sense of velocity, and conveys a lively vitality.

In the same year the Piano Sonata was composed, other works such as the Piano Concerto No. 1 and the suite Out of Doors were also created. Subsequently, through works like the String Quartets Nos. 3 and 4 (composed between 1927 and 1928) and the Piano Concerto No. 2 (1930-1931), Bartók moved towards his mature period, beginning with the String Quartet No. 5.