The 19 organ preludes form the core of Buxtehude's work and are ultimately considered his most important contributions to music literature of the 17th century. They are sectional compositions that alternate between free improvisatory sections and strict contrapuntal parts, usually either fugues or pieces written in fugal manner; all make heavy use of pedal and are idiomatic to the organ. These preludes, together with pieces by Nikolaus Bruhns, represent the highest point in the evolution of the north German organ prelude, and the so-called stylus phantasticus. They were undoubtedly among the strongest influences of JS Bach, whose organ preludes, toccatas and fugues frequently employ similar techniques.

The preludes are quite varied in style and structure, and therefore hard to categorize. Structure-wise, there usually is an introductory section, a fugue and a postlude, but this basic scheme is very frequently expanded. Both BuxWV 137 and BuxWV 148 include a full-fledged chaconne along with fugal and toccata-like writing in other sections, BuxWV 141 includes two fugues, sections of imitative counterpoint and parts with chordal writing. A few pieces are smaller in scope as for example, BuxWV 144, which consists only of a brief improvisatory prelude followed by a longer fugue. The sections may be explicitly separated in the score or flow one into another, one ending and another beginning in the same bar. The texture is almost always at least three-voice, with many instances of four-voice polyphony and occasional sections in five voices.

BuxWV137

Prelude, Fugue and Chaconne

4:57

Schmidt, O.