The Prelude opens Volume 1 of The Well-Tempered Clavier, a cycle of preludes and fugues for keyboard instruments by Johann Sebastian Bach.
Written in 4/4 in sixteenth durations, it has two voices. The harmony of the prelude is generally similar to that of Bach's time. Its tempo is not too fast. In its deviations, the prelude indirectly touches many tonalities in which preludes and fugues will be written later. On the whole, the Prelude gives rise to a feeling of infinity, of immense space, and this is helped by the “pure” tonality of C major. A sense of lightness and spaciousness appears.