Her crime was to issue a heartfelt denunciation of the wrongheadedness of President George W Bush’s “war on terror”.

The hate mail and false accusations that followed provided the impetus for her new novel. “Having lived through it, I felt qualified to write about it, but wanted to do so from the inside of this experience in a way that will really throw light on it,” she says on the phone from her Appalachian farm. Turning the experience

into something positive was a personal release: “I know what it feels like to have your writing misconstrued. I felt the only way to become reconciled with this was to understand the enemy vision and try to construct something useful. It was wonderfully cathartic”.

The result was The Lacuna, but in the seven years it took to write, it grew to encompass the household of the Mexican painters Diego Revera and Frida Kahlo, while they were providing shelter to the exiled Trotsky, and the anti-communist witch hunts of the United States in the 1950s.

As with The Poisonwood Bible, the novel that made Kingsolver an international bestseller (it was the favourite of UK book groups in 2005), there is considerable personal history woven into this tale. Like his creator, her central character, Harrison Shepherd, becomes a bestselling author who then suffers vilification when his writing is deemed unpatriotic. This was, she says, because it was the perfect vehicle for her plot: “I’ve always felt a taboo about writing from the point of view of a writer, because I thought people would find it boring. In the beginning I wasn’t at all sure that he would become a writer, but it became clear that it would be the perfect career for him and thought: ‘What good luck. I know a lot about that.’”

‘Validating experience’

Kingsolver protests that, unlike Shepherd, who rockets to fame from the publication of his middlebrow first novel, she “was blessed with a slow build-up”. By The Poisonwood Bible, her fifth novel, she had an assistant who could handle the fan mail. Shepherd’s dependence on his assistant, Violet Brown, becomes a key relationship in The Lacuna.

Its framework – of diaries discovered long after the events they record – distances the reader. Despite this technical challenge, Kingsolver has deliberately added the additional barrier of having Shepherd write his diaries in the third person.

“From the beginning, I knew I had to present this character in a very unusual way because he cannot inhabit his own body because he is so afraid of being visible. It took me a couple of years to get into the persona and discover the voice so that it would come naturally to write in that way. But it does create a distance.” So much so, that the trusted readers to whom she gave the earliest drafts urged her to change the structure. She resisted, at the cost of having to complete the first draft without testing reaction. It seems that this faith in the revelatory power of the personal journal stems from keeping a diary since childhood.

“Writing has always been my way of validating experience,” she says, hastily dispelling preciousness by adding that, with a full family life, keeping a diary now tends to be confined to episodes of travel.

She has, however, mined one of her travel journals from a visit to the Yucatan peninsula to provide the background for a trip Shepherd takes to research one of his novels, and her fascination with Mexico (she spent 20 years living close to the border in Arizona) runs through this novel. Her life, thoroughly rooted in the real world of farming and motherhood, is the springboard for an uncanny knack of producing books which chime with the zeitgeist, sometimes in the most unlikely way. American foreign policy in the Congo, the background to The Poisonwood Bible, would have been the exception here, but publication coincided with renewed war there in 1998. Animal, Vegetable, Miracle, published in 2007 during The Lacuna’s gestation period, a memoir of her family’s year of living entirely on local produce combined with an analysis of America’s relationship with food, reflected the increasing concern about where our sustenance comes from. It is a perpetual theme. Food, especially the making of celebratory meals, is a comforting thread running through the new novel. Shepherd, having learned first-class kitchen skills at an early age from his mother’s Mexican cook, uses them to secure his path through a life strewn with uncertainty. And, like Kingsolver, his cooking is both pleasure and necessity, but always secondary to his writing.

Art and life

The Lacuna follows renewed interest in the art and life of Frida Kahlo and its publication comes hard on the heels of a substantial new biography of Trotsky. Kingsolver sees him – another compulsive diarist also made into a villain in the public imagination – as something of a lacuna and felt a desire to flesh out the bones of his exile in Mexico as well as our understanding of Kahlo.

The affair between the two is significant to the narrative. Shepherd moves from being Kahlo’s cook to Trotsky’s typist, a transfer which will have eventual repercussions. The detailed descriptions of Kahlo contrast pointedly with our limited picture of Harrison Shepherd. He lives up to his name by being the reader’s guide through his life story, but we see the events he chronicles largely through his eyes and therefore lack a rounded picture. Instead of interaction with others providing a mirror to his character, Kingsolver employs the diary device as a microscope. We see beneath the surface in fascinating detail, but cannot see the whole.

This is a frustration, for which the author provides a rationale. Lacuna is more than the title of this book. It is a concept explored in all its variety: literary (a missing diary is significant), geological (as a boy Shepherd is fascinated by a hidden sea cave), cultural (between the United States and Mexico) and moral (between perception and reality).

Kingsolver has a track record of books which can be read either as straightforward narrative or allegorically as a critique of current orthodoxies. Her quiet voice becomes indignant as she says: “In both 1949 and the modern era there is the phenomenon of the howlers, the howling which is transmitted through the media. It is not just the gossip papers. We have just seen the balloon boy (a hoax perpetrated by the parents of a small boy who was supposedly adrift in a hot-air balloon) in the serious papers. If we are willing to accept this flippy stuff as news, we bear a responsibility. I wanted to examine in this book what it is in us that wants to believe the worst in people and I want to urge people to consider that, whatever you might think you know, you never know the real story.”

This rant against modern media “may not be the smartest thing for someone who is about to do the round of interviews to publicise a new book”, she concedes, but remains unapologetically combative about it. With reason: as the blogosphere blurs the boundaries between unverified hearsay and established fact, this matters more than ever.

The dangers inherent in transmission of what is at best prejudice and at worst malice in the guise of innocent gossip have been explored in every possible literary form over centuries. Kingsolver’s take on it has produced a compulsive read in which the separate narrative strands are deftly woven together, but with the flaw that the development of its central character has been lost in the process.

Her thesis has got in the way of her fictional world: “It’s a fact of our culture that the loudest mouths get the most airplay, and the loudmouths are saying now that in times of crisis it is treasonous to question our leaders. Nonsense. That kind of thinking let fascism grow out of the international depression of the 1930s.” The moral of this tale (and Kingsolver, as always, has a moral impulse here) is that, “there is always a missing part of the story and it is wise to withhold judgment”. Even so, the reader can’t help wishing that, instead of looking through a historical perspective, Kingsolver had used her storytelling gifts to focus on today’s loudmouths.

The Lacuna, by Barbara Kingsolver is published by Faber & Faber, £18.99.