The analysis of the preludes must be regarded inthe light of a supplement to my work. AS the preludes stand in close Spiritual relationship to the fugues, it seemed to me that I had to consider them with regard to their Spiritual contents; the technical (harmonic-metrical) analysis will not, however, I trust, be without its use. The astonishing Simplicity and strict logic of the harmonic and modulatory structure causes these pre ludes to rank as truly classical models of developmen't from Short motives; future generations may study them again and again with profit. The harmonic schemes here communicated may be turned to most useful account if advanced readers try to work them. Out from figured bass at the pianoforte, but with other motives than those developed by Bach; the schemes may also be transposed and worked out in a similar manner, and the diversity of form which results, the utmost Simplicity notwithstanding, will afford just cause for astonishment.