I just got a new book in the mail:
Lorraine Murray, The Abbess of Andalusia (Charlotte, NC: St. Benedict's Press, 2010), xxxiii+233pp.
There have been several studies of O'Connor, none of them entirely satisfactory. The most recent, Brad Gooch's Flannery: A Life of Flannery O'Connor, which I read last Christmas, is good in most respects but it signally fails in the most crucial: O'Connor's Christian--and specifically Catholic--faith, which Gooch rather severely downplays, perhaps finding it de trop for his tastes. Earlier studies were much worse. I shall see if this new book is any better. Admittedly she's not an easy person to describe, much less to pigeonhole. She deliberately and perhaps rather gleefully blows up "conventional" categories, both literary and theological.
It occurs to me--as I'm doing research for a paper for an academic conference in September of next year on literature and theology--that someone should do a study (if it's not been done already, and I don't think it has) of O'Connor's characters as, conceivably, a "Western" example of the well-known Eastern (and especially Russian) phenomenon of the "yurodivy," that is, the fools for Christ. Her characters are forever doing things whose outrageousness matches that of figures in Tolstoy and Dostoevsky, figures whose paradigmatic examples include St. Simeon Salos, St. Andrew of Constantinople, and, more recently, St. Xenia of Saint Petersburg. These fools have been analyzed in a number of articles and books over the years, the best of which (according to Peter Bouteneff's review in Logos: A Journal of Eastern Christian Studies in 2008) is:
Sergey Ivanov, Holy Fools in Byzantium and Beyond, trans. Simon Franklin (Oxford UP, 2006).
One other very useful resource I have recently come across is the work of the scholar Svitlana Kobets, much of which is very helpfully available in Russian and English here.