Often, they adapt the works they offer to meet particular conditions.
Centuries-old works written for instruments that have become obsolete may be adapted for ones currently in use.
Such an approach meant presenting music in the forms with which musicians and audiences of the present were familiar; when in 1829 Felix Mendelssohn revived J. Bach's Retrospective editions followed the same practice: this meant that realized continuos might be provided; lyrics would be syllabified and underlaid with a precision lacking in many earlier sources; and accidentals would be handled in accordance with modern conventions.
Moreover, nineteenth-century notation regulated many more aspects of music than had the notations of earlier centuries, and since prospective users were accustomed to the guidance provided by nineteenth-century texts, editors might supply performance suggestions that nineteenth-century musicians would expect but that texts predating the late eighteenth century might not provide.
When Foucault penned his , he was thinking about literary works, but his insight is equally valid for any of the creative arts for which editions are prepared—literature, drama, or music.
The implications of Foucault's observation—and its corollary—are especially intriguing for music, where two sorts of editions, intended for different musical communities, reflect two different concepts of the musical work and two different views of the functions of the musical text.
Restated in less provocative form, Foucault's observation reminds us that what an editor does—the sort of edition that he sets out to produce, the sorts of decisions that he makes at each stage along the way, the uses that he thinks his edition will serve—is dependent upon what he believes a work to be.
And Foucault's observation has a corollary: different ideas of what a work is generate different sorts of editions.
Historical musicology, effectively a species of , was being born, and many of the practitioners of this new discipline came to see musicological editions less as means to performance than as texts of record.
For such musicologists, the introduction of editorial performing suggestions seemed "unscientific," and by the end of the nineteenth century there had arisen a demand for editions that not only made the music of the past available but that presented that music in the forms in which it had originally been inscribed and disseminated.