Flannery O'Connor's stories plough a straight and often gory furrow from individual pride to disaster. Writing the way she did "because (not though) I am a Catholic", she described A Good Man is Hard to Find, the first of her two story collections, as "nine stories about original sin, with my compliments". This religious flavour, coupled with the great economy of her prose, and a tendency to focus on two characters inextricably and antagonistically tied to one another, might have made parables of her stories. But the unruly life she invests them with, not to mention her deliciously skewed sense of humour, stops them attaining the clearly defined edges of the purely instructional. "As with the work of any profound artist," Robert Towers notes, "an element of the mysterious – of the unspoken, the unacknowledged – hangs like a shining mist over all that has been consciously intended and consciously achieved."

The English professor Walter Sullivan once compiled a bloody catalogue. Of the 19 stories published in O'Connor's short lifetime (she died from a kidney infection in 1964 at the age of 39, having been diagnosed with lupus in 1950), nine end in one or multiple violent deaths, three in physical assault, one in arson, and two in theft. O'Connor's tongue was in her cheek when she said, "I can't write about anything subtle", but she knew a good joke has its roots in the truth. Her stories are baldly dramatic, and the Georgia she creates on the page – as individual a landscape as any in fiction – is summoned with few, very bold strokes. The sun is "a huge red ball … drenched in blood", a "furious white blister", a "white hole like an opening for the wind to escape through in a sky a little darker than itself". The "fat yellow moon" is seen in the branches of a fig tree "as if it were going to roost there with the chickens". O'Connor so loads her brush with pathetic fallacy that her landscape is alive, the scene nearly always hemmed in by lines of watching trees or woods that gape "like a dark open mouth".

The figures she plants in this landscape –farmhands, conmen, embittered intellectuals, bigots, Bible salesmen and killers – are equally vivid, and the situations they encounter yet more so. Speaking of the disjunction between her Catholic convictions and what she saw as her largely godless readership, O'Connor wrote that "[w]hen you can assume that your audience holds the same beliefs you do, you can relax a little and use more normal means of talking to it; when you have to assume that it does not, then you have to make your vision apparent by shock – to the hard of hearing you shout, and for the almost-blind you draw large and startling figures." The most famous example of this approach, O'Connor's quintessential story, is "A Good Man is Hard to Find" (1953), in which a family encounter the gang of an escaped convict, The Misfit, in the Georgia backwoods. As O'Connor has it, the story's meaning resides in a moment of grace enacted when the grandmother, up until the conclusion of the story solely foolish and self-serving, touches The Misfit's shoulder and tells him,

'Why you're one of my babies. You're one of my own children!' She reached out and touched him on the shoulder. The Misfit sprang back as if a snake had bitten him and shot her three times through the chest.

It's an indelible moment, yet despite O'Connor's own explanation it is interpretable in many different ways. O'Connor's ability to create characters and situations that resonate as powerfully as they do results in meanings that, as she herself acknowledged, ramify beyond authorial intention. A parable only possesses its surface meaning and actual meaning, but O'Connor's most accomplished stories can seem to point in all sorts of directions at once. Elizabeth Bishop succinctly captured this paradoxical trait when she pointed out that "[y]ou'd have to call 'A Good Man is Hard tßo Find' a 'funny' story even though six people are killed in it".

But if the potential meanings of O'Connor's stories are numerous and plastic, their internal logic is singular and concrete. O'Connor is so sedulous an observer of Chekhov's gun rule that if a family discusses a newspaper story about a killer on the loose, there is no doubt that he'll massacre them; if a bull is roaming the fields, its horn will soon be buried in someone's gut ("Greenleaf"); if a grandfather has bred his own obstinacy into a beloved granddaughter, he will beat her to death when she is obstinate towards him ("A View of the Woods"). The inexorability of O'Connor's plots can, as in these cases, invest her stories with the awful power of Greek tragedy, and indeed before giving readings of "A Good Man is Hard to Find" she'd say that, "like the Greeks you should know what is going to happen in this story so that any element of suspense in it will be transferred from its surface to its interior". If someone's first experience of O'Connor was "The Displaced Person" (1954), at the denouement of which three people passively watch a tractor roll down a slope and crush a fourth, the event would be unexpected and shocking. But the story is arguably more powerful when a familiarity with O'Connor's work makes this ending an awaited inevitability. The tangible menace that her stories exude isn't about "what", but "when".

When her control is less certain, as in "A Stroke of Good Fortune" (1949) or "A Late Encounter with the Enemy" (1953), such an approach can seem a gimmick, calamity arriving like the punchline to a poor joke. Failures like this explain why some critics consider O'Connor's art brilliant but narrow and predictable. But such instances are in the minority, and the late stories "Revelation" (1964) and "Parker's Back" (1965), suggest her talent was only deepening as her life ended. It's tempting to wonder what she might have done with more time, not least to see how the "Christ-haunted" South of her fiction would have been altered by the Civil Rights Act, passed a month before she died. Her position on race was ambivalent, but I tend to agree with Hilton Als that she was "not romantic enough to take Faulkner's Disney view of blacks – as the fulcrum of integrity and compassion. She didn't use them as vessels of sympathy or scorn; she simply – and complexly – drew from life". That same collision of the simple and the complex is what lies at the heart of her best work, a tight compact of the bold, the startling, and the mysterious.

Next: Frank O'Connor