Anne Enright became briefly notorious when she wrote about “disliking” Kate and Gerry McCann, five months after their three-year-old daughter Madeleine disappeared in 2007. Her target was the hair-trigger culture of condemnation that awaited the parents, but the difficulty and value of her essay lay in how she made no bones about having gossiped and speculated about them herself. While it was inevitably spun as a callous attack, anyone who went from the outraged newspaper reports to her novels would have found a writer whose chief virtue lies in refusing to hold her reader’s hand.

Enright’s previous novel The Forgotten Waltz (2011) - a story of adultery set against boom and bust in her native Ireland - left you reading between the lines to decide whether the narrator was a home-wrecker or just a woman in love. Like The Gathering (winner of the 2007 Man Booker Prize), it was told in the first person and cut dizzyingly between multiple time frames. Enright parcels up her new novel into date-stamped portions bearing the names of each of the five main characters. If it looks more conventional, this is about the only thing The Green Road spells out.

The first segment is set in 1980 in a small rural town in the west of Ireland, where the farmer’s wife, Rosaleen, takes to her bed after her oldest son, Dan, announces his intention to join the priesthood. The next thing, it’s 1991, and Dan’s been on New York’s gay scene for five years: we don’t retrace his steps, and while the sequence bears Dan’s name, he’s offstage for most of it. Enright narrates here in the first-person plural - the voice of a gay community swapping war stories - to chart an art dealer’s love for a picture editor strung along by handsome “Irish Dan”.

Next we fast-forward six years, recrossing the Atlantic to join Dan’s sister Constance, mother to three teenagers, as she awaits a mammogram, with “no gap - or none that she could discern - between breast-feeding and breast cancer”. In 2002, we’re in Mali with his younger brother Emmet, an NGO worker in a dying relationship with a colleague; in 2005, it’s Dublin, with his sister Hanna, a stalled actress and new mother, “back in her skinny jeans, but what was the point…?”

Someone says Dan tells you “everything except the thing you needed to know”. The Green Road is like that. No one is happy - Constance pops “a little Seroxat”; Hanna gets so drunk a paramedic has to lift her off the kitchen floor; Emmet has had a breakdown - but we don’t know much about why. The omens are not good when Rosaleen invites them all back to the tumbledown family home for one last Christmas.

Unlike The Gathering and The Forgotten Waltz, no clinching backstory surfaces. When Rosaleen wonders, “Where did it begin?”, we’re not even sure what “it” is.

“It’s like there’s some secret… but there just isn’t,” says Hanna. Attempts to talk fail: “‘My own children,’ [Rosaleen] said, as though they had ganged up against her in some terrible way. ‘Your own children what?’ said Emmet. ‘My own children!’”

Rosaleen can be a pain, needling Constance about her weight, suggesting Emmet could be impotent, but it’s possible, too, that her children simply await the stage Enright describes in her non-fiction work Making Babies (2004), when “most of us come to an accommodation between the “MOTHER!’ in our heads and the woman who reared us”.

The Forgotten Waltz used Ford Madox Ford’s 1915 adultery tale The Good Soldier as a model. Here the touchstone might be Jonathan Franzen’s The Corrections (2001). Where that novel wove together decades of back story in the run-up to a family’s last Christmas, The Green Road is more fragmented. The novel’s structure of discrete short stories shows the Madigan children as satellites out of sync. When their mother goes missing after roaming the coast alone on Christmas night, her children form a search party, groping in the dark, adrift from her and each other. It’s a climax that works as drama and symbol.

Enright withholds closure but doesn’t skimp on pleasure. Barely a page goes by without a striking phrase or insight. She convinces you of her setting, whether it’s west Africa or the East Village. The sons’ stories, unfolding farther afield, are story-driven; the energy in the daughters’ stories comes from the texture of experience (a supermarket run; half-cut on vodka).

Enright’s gifts of observation and imagination can lull you into overlooking how radical she is formally. She has said that “the unknowability of one human being to another” is “an endless subject for novelists”. If one of the pitfalls for any realist novel is the sense that the characters are reverse-engineered to serve an authorial design, Enright’s characters have a solidity for not being explained to every last fibre of their being.

You could see The Green Road as virtuosic but inconsequential, but in its loose ends is a bold and brilliant way to approach the sadness of a family that fails to connect.