The preludes was written in all tempered keys. Some Preludes is also descriptive and didactical

Prelude No.01 (C Major) - Arpeggios Prelude No.02 (A minor) - Scales, 5 Fingers Exercise Prelude No.03 (G Major) - To 4 and 5 Finger Prelude No.04 (E minor) - The baby sleeping Prelude No.05 (D Major) - Cantabile, expression (The Cello) Prelude No.06 (B minor) - Current, flow of water Prelude No.07 (A Major) - Expressive, legato - cantabile Prelude No.08 (F# minor) - The Clock Prelude No.09 (E Major) - Octaves in high speed Prelude No.10 (C# minor) - Exercise for the thumb Prelude No.11 (B Major) - Cantabile, expression Prelude No.12 (G# minor) - Arpeggios, broke chords Prelude No.13 (F# Major) - Broke Chords Prelude No.14 (Eb minor) - The Waterfall Prelude No.15 (Db Major) - Expression (Music Box prelude) Prelude No.16 (Bb minor) - Five fingers in opposite mov. Prelude No.17 (AB Major) - The Butterfly Prelude No.18 (F minor) - The funeral - To my father) Prelude No.19 (Eb Major) - Independence of the fingers Prelude No.20 (C Minor) - Broke chords (The Ocean Waves) Prelude No.21 (Bb Major) - The Sunrise Prelude No.22 (G minor) - The Wind - Gale Prelude No.23 (F Major) - The Children playing Prelude No.24 (D minor) - The romance Prelude No.25 (A Major) - Broke chords in high speed Prelude No.26 (D minor) - Tempest Prelude No.27 (Gb Major) - Arpeggios Prelude No.28 (D Major) - Expression, arpeggios Prelude No.29 (Ab Major) - The Births flying