3 by Flannery O'Connor collection that I've been working my way through is The Violent Bear it Away (1960), O'Connor's second and final novel.
Tarwater is a 14 year-old orphan who was born right after the car wreck that killed both of his parents and his grandmother. He is first taken in by his mother's brother, Rayber, but shortly afterward is kidnapped by his great-uncle, a man who lives in an isolated shack in the country and who believes he is a prophet who is destined to baptize baby Tarwater and raise him to carry on his prophecy after he dies. Oddly enough, the great-uncle did the same thing to Rayber back when he was seven, and although Rayber was only there for a few days before his father brought him back home, it greatly affected his childhood and led to him completely rejecting God as an adult. Rayber tries to get little Tarwater back, and brings a social worker with him, but the great-uncle shoots at them and they run away (and eventually get married and have a mentally handicapped son named Bishop). Rayber doesn't try to rescue his nephew again, and Tarwater isn't free of his great-uncle until he dies when Tarwater is 14. That sets off the action of the novel and the struggle of both men to reconcile their experiences with the crazy uncle, their mutual suspicion that they might actually be prophets, and their need for one another