The Performance of History: Motivations for Revivalist Participation in Sacred Harp of the Chesapeake Bay Area. Brigita Lee Sebald, Master of Arts thesis, University of Maryland, 2005
I think this goes well with Kiri Miller's new book, and might be an interesting read before you buy Kiri's book.
The thesis is about the folklore revival setting of Sacred Harp in the Chesapeake Bay area, which includes parts of Maryland, Virginia and Pennsylvania. Brigita Sebald looks at Sacred Harp in this setting and views it in its relation to the national Sacred Harp scene.
In recounting the history of Sacred Harp, Sebald picks up a few historical inaccuracies that are not correct (in my opinion). I discuss some of these inaccuracies in Rethinkin our thinkin (though independently of any relation to this thesis). I highly recommend that you read this if you are interested in Sacred Harp. Just click on the first link to go to the pdf document.
Note: I originally intended to write more in detail about The Performance of History, but it was so long after reading it until I got around to writing this, some of the "energy" had worn off.