The music editor is responsible for every musical and literary element on the page. Everything from accidentals to chord symbols to misspellings to wrong notes are his responsibility. Many times the editor also is involved in project management: managing a project, working with the creators from start to finish, keeping them on target and getting the project completed.
As related to music editing, my background includes the position of Creative Director for Musicals and Collections for Word Music.
Music editing and project management services are available to publishers and can be combined with music engraving service if desired.