Given the pride that organists felt in their improvisations, some were reluctant to write their pieces down or to disclose copies. In Der musicalische Quacksalber, Kuhnau described the musician who, if possessing ‘a beautiful piece, would rather allow his jacket and trousers to be taken before he would communicate one note to another musician. If he is supposed to perform before someone whom he suspects can learn something from him, he deliberately brings nothing good to the market. I know that once an excellent organist in the presence of an attentive devotee played as if his fingers were weighted with lead and as if he had chosen the [elementary] motets of [Andreas] Hammerschmidt as his chief study, even though he knew there was another person present who could recommend him to a great prince and thus help him attain an imposing salary.’ One such organist who may have been tempted to secrecy was Buxtehude’s friend in Hamburg, Johann Adam Reincken. In his sole surviving publication—a book of trio sonatas, Hortus musicus (1688)—Reincken expressed reluctance to publicise his works, a reluctance that may also be evident in the paucity of his extant output. There are only five known organ pieces by Reincken, although it is possible that more are now lost.

Buxtehude, by contrast, was happy to write down his organ compositions and share them with other players. He sent many pieces in his own hand to the central German theorist Andreas Werckmeister, and these copies were later passed to Bach’s cousin, Johann Gottfried Walther. Further pieces may have been written down for his pupils or even dictated to them in the course of a lesson. Certainly the examples of other organists, such as Bach or Sweelinck, suggest that a major reason to compose was to provide a model repertoire for pupils.

Yet none of Buxtehude’s organ pieces has survived in autograph. The majority of his organ output is preserved in sources compiled by central German organists of later generations, such as Walther or members of the Bach circle. Although some of these manuscripts may stem from copies made by Bach during his visit in 1705, the fact remains that they are third- or fourth-hand sources. Whereas Buxtehude would have notated his pieces in German organ tablature, Walther and the Bach circle used staff notation. Inevitably they introduced errors, and also added ornamentation and indications of manual-changes to suit their own taste. Consequently the surviving sources of the organ works are difficult to interpret, and a plethora of modern editions has appeared, each with its own reading of the sources (particularly for the praeludia and other free works). Klaus Beckmann’s edition seeks to strip away apparent accretions added by copyists, in the belief that his stylistic insights allow him to reconstruct Buxtehude’s intentions. By contrast, Michael Belotti’s edition takes one source as the basis for each piece, and presents the praeludia on two staves to give the player more choice over where to use the pedal.

The impossibility of finding a definitive text for Buxtehude’s keyboard works reflects, above all, their improvisatory nature. These are pieces that might be different in each rendition or might be constantly changing their shape in the player’s mind. Many include improvisatory features, such as toccata-like flourishes, lengthy pedal solos, or chaconnes where the enthusiastic player might be tempted to add a few more variations. Buxtehude’s praeludia are typically in a sectional form, with frequent contrasts between fugal and toccata-like textures; often these contrasts are dramatic or unexpected, suggesting that the organist can turn the music in whichever direction he wishes.