Composed between 1926 and 1939, a period when Bartók's creative drive was at its peak. It consists of 153 pieces across 6 volumes. It was conceived as piano etudes for pedagogical purposes for his son Péter, born from his remarriage to Ditta Pásztory (Volumes 1 and 2 are dedicated to his son).

• Volume 1: 36 pieces (Nos. 1-36)
• Volume 2: 30 pieces (Nos. 37-66)
• Volume 3: 30 pieces (Nos. 67-96)
• Volume 4: 25 pieces (Nos. 97-121)
• Volume 5: 18 pieces (Nos. 122-139)
• Volume 6: 14 pieces (Nos. 140-153)

Volumes 1-3 can be used by piano beginners. Volume 4 is recommended to be used in conjunction with other pedagogical materials of a similar level. The collection increases in difficulty and artistic merit with each successive volume; particularly from Volume 5 onwards, the pieces reach the level of concert repertoire. Characteristic features include the use of folk melodies, modes, pentatonic scales, whole-tone scales, irregular rhythms, changing meters, and dissonance. It would be ideal as a challenge for familiarizing oneself with these modern elements, which differ from traditional teaching materials.

Volume 6

• 140. Free Variations
• 141. Subject and Reflection
• 142. From the Diary of a Fly

• One of the most popular pieces in the collection. The dense musical movement evokes the buzzing of a fly.
• In the middle, “the fly's monologue” is written.

• 143. Divided Arpeggios
• 145. Chromatic Invention
• 146. Ostinato

• A very fast-paced and rhythmic piece. A concert-worthy miniature.

• 147. March
• 148-153. Six Dances in Bulgarian Rhythm

• Bulgarian rhythm refers to rhythms frequently used in Bulgarian folk music. It involves dividing eighth notes within a measure into unequal units, and this rhythm has already appeared in Nos. 113 and 115.
• It is also well-known that this rhythm appears in the central movement of the String Quartet No. 5.
• This piece was dedicated to the female pianist Harriet Cohen.
• Bartók himself performed this piece at a concert in Budapest.
• Other folk-inspired pieces include:

• 15. Peasant's Song
• 40. In Yugoslavian Mode
• 43. In Hungarian Style
• 68. Hungarian Dance
• 74. Hungarian Song
• 109. From Bali