The new Document Sets feature was proposed and funded by Adam Rabinowitz and the University of Texas-Austin Classics Department to support the presentation of sub-sets of works within a collection to different audiences.
One use case might be the presentation of an "exhibit" of an author's papers relating to a theme -- personal correspondence vs. professional correspondece, or political topics vs. business negotiations with an editor. Imagine Davidson's Complete Works of George Orwell divided into sets of "Wartime Broadcasts for the BBC", "Negotiations with Publishers", "Book and Pop-Culture Reviews", "Writing about WW2", "Papers relating to Animal Farm", and "Papers relating to 1984". In such a case, works would be selected from the collection on thematic lines, but many works would appear in two or more thematic sets.
Another use case--one particularly suggested by Adam's classroom use with the Terrell Papers--is that of a collection of only partially transcribed works, edited by students in a classroom. In that case, the works might be hidden from the public until they had been reviewed for quality (by the general editor or the classroom instructor, depending on project), and only then exposed to researchers outside the transcription project. In addition, a sub-set of an exhaustively digitized collection might be chosen to be the focus of a transcription/translation effort, adding works from a private collection to a private document set created to direct the efforts of a particular classroom or team.
To support document sets, with their dual roles controlling access and presentation, I've built a set of features accessible to collection owners. To enable document sets, go to your collection, choose "settings' and hit the "Enable Document Sets" button. This will add a new "Sets" tab to your collection screen to manage its document sets.
Creation, editing, and assigning works to document sets will be, I hope, entirely straightforward. Nevertheless, I'm concerned about the possibility that documents may be made public accidentally. I've added indicator text about the default state of works and the public status of document sets, which I hope will prevent private material being made public. If you have any suggestions for making this clearer or easier to use, please let me know.