About a third of the way in, I was discussing this book with my husband, who asked: “So is the author a genius or is she just very good?” “Well, she is definitely a genius,” I said. “But I don’t know how good she is, yet.”

“Genius” was always a term that contained arguments about art and order and the relationship of the writer to society - whether he (there were no female contenders) was sacrifice or magus, mad artist or Great Novelist. There may be another argument here, if we had time to unpack it, about modernism and the rise of the middle classes. These days the middle classes are in decline and the term has gone out of fashion, though we still retain the sense of the genius as someone who is brilliantly “beyond”; who breaks the rules and plays the edge.

Eimear McBride is that old fashioned thing, a genius, in that she writes truth-spilling, uncompromising and brilliant prose that can be, on occasion, quite hard to read. Here, for example, are the opening lines: “For you. You’ll soon. You’ll give her name. In the stitches of her skin she’ll wear your say.” If this kind of thing bores or frightens you, then there are many other wonderful books out there for you to enjoy. The adventurous reader, however, will find that they have a real

Here, for example, are the opening lines: "For you. You'll soon. You'll give her name. In the stitches of her skin she'll wear your say." If this kind of thing bores or frightens you, then there are many other wonderful books out there for you to enjoy. The adventurous reader, however, will find that they have a real book on their hands, a live one, a book that is not like any other.

A ranting, Catholic mother, a disabled brother and a pervy uncle: these may be bog-gothic standards of any Irish book season, but McBride brings passion and and distance with the voice of her highly dissociated protagonist, whose name we never get to hear. The “you” of the book is her older brother, whose brain was damaged by the removal of a tumour in infancy, and the love she has for him is a clean space in a soiled world. She imagines a strange underground, pre-sexual life for them together, “In burrows rabbits safe from rain … You and only me.” The brother’s condition makes him both cause and cure of all her guilt - and this is a novel soaked in guilt.

“Morning noon and night and this is what you do to me?” You can almost hear the blows in the rhythm of the words. The narrator’s mother is deeply troubled and her childhood both chaotic and cruel. Puberty brings a power that is scarcely hers to control. After a sexual encounter with an uncle, she becomes that figure much loved by male fiction writers - the girl of uncertain background who lifts her skirt at school. The events of the book are simple and not so much described as powerfully evoked. Her grandfather dies, her brother’s life goes downhill. Meanwhile, our heroine goes to college and pursues a career of shame and abandonment, seeking damage and defilement in a trail of sexual encounters that are anonymous, aimless and finally, horribly masochistic. “The answer to every single question is Fuck.” Drink may be involved, but the way the narrator inhabits - or fails to inhabit - her own account feels more French than Irish. Marguerite Duras and Catherine Millet come to mind as much as Sean O’Reilly or Edna O’Brien. She is affectless and highly transgressive - in her attraction to an older man, in her need to become a debased object; to break through pleasure and protect herself from the disaster that is desire.

Or perhaps that disaster is present throughout, in the constant fragmentation of the syntax. There are moments when you long for the style to settle down, or evolve; the prose at 18 is just as broken as it was at five. But the style is also direct, simple and free of intertextual tricks and, after a while, the language becomes its own kind of object. The narrator is better at hearing things than telling them: there are riffs of reported speech and scraps of banter, and these are put to virtuoso use in building scenes and describing action. There is also, surprisingly, a strong storyline when, at the grandfather’s funeral, what seemed aimless becomes completely gripping. This book is hard to read for the best reasons: everything about it is intense and difficult and hard-won.

The result is an instant classic - an account of Irish girlhood to be set alongside O’Brien’s The Country Girls for emotional accuracy and verve, and the sense of its overwhelming necessity. A Girl Is a Half-Formed Thing is completely modern in its sensibility and completely old-fashioned in the way it triumphantly ignores the needs of the book market. It took nine years, apparently, to find a publisher. Who forgot to tell Eimear McBride about the crisis we are in and about the solution to that crisis: compromise, dumb down, sell your soul?