In 1993, two years after Svetlana Alexievich published Boys in Zinc, her oral history of Russia’s war in Afghanistan, she was sued by a number of the people she had interviewed. They accused her of offending their “honour and dignity” and of portraying their soldier sons as “soulless killer-robots, pillagers, drug addicts and racists”. Though the case was in part thrown out, it said much about the fickleness of memory and the way that the rawness of grief – conveyed to Alexievich during the interviews – had quickly been overlaid by a more bearable narrative, in which the war had been a heroic venture to help Afghanistan create a new society: their sons and husbands had not died uselessly but for a noble cause. Alexievich would not have attended the court hearing, she wrote later, except that she felt it her duty to confront her accusers, not to apologise to them, but to “ask their forgiveness for the fact that it is not possible to get at the truth without pain”.

All non-fiction writers are vulnerable to charges of invention and distortion, and none more so than Alexievich, who has spent more than 40 years producing her own remarkable version of recent Soviet history, one based exclusively on interviews, strung together as a series of monologues, unmediated by commentaries. Oral history was not recognised as professional research by the Russian Academy of Sciences, and Alexievich’s books have attracted repeated criticism in a country where the state has kept tight control of its history through the media, school books and anniversary celebrations, ensuring a shared, tidy and victorious collective memory of the past. Her subversive, anguished testimonies, taken from ordinary people, have not been appreciated. When, in 2015, she was awarded the Nobel prize for literature – the first journalist to be so honoured and credited with inventing a new literary genre – it was greeted with outrage in the state-controlled Russian media, which claimed that she had won it only on account of her anti-Putin views.

Last Witnesses, now published in English for the first time, and translated by Richard Pevear and Larissa Volokhonsky, first appeared in 1985. A logical sequel to her first book, The Unwomanly Face of War – interviews with the women who served in the Red Army, which sold more than 2m copies – it captures the memories of people who had been children, aged between three and 14, during the second world war.

Many of her hundred or so testimonies open on the day the war broke out, a time recalled as cheerful: the weather was good and children were out playing with friends or picking mushrooms. All too soon, horrors accumulate. Safety is brutally replaced by fear, pain and hunger. With the arrival of the Germans, in their “stomping iron-shod boots”, fathers are lined up and shot, mothers killed by bombs, houses set on fire. For most of these children, the war was spent in an orphanage, living with a grandparent, or being put to work in a hospital. They forgot that they were children. There are accounts of entire villages being torched, of people eating dirt and grass, or seeing the families of partisans hanging from trees and frozen stiff, so that the bodies tinkled when they swung in the wind.

Like her Red Army female soldiers, who survived to return home in 1945, few of the people Alexievich interviewed found the end of the war easy. They came back to their villages in which all the men were dead, and where unexploded mines continued to cause casualties. The sense of loss, ever present in Alexievich’s work, is the theme that binds these memories – loss of siblings, pets, possessions and above all mothers – along with an abiding feeling of being too afraid ever to be happy again, because happiness is something that cannot last.

Alexievich is not the first person to draw on oral history in Russia. The writer she considers her mentor, the fellow Belarusian Ales Adamovich, put together in the 1970s a history of the siege of Leningrad, based on “epic choruses” provided by interviews and diaries. Like hers, his work was sufficiently unpopular with the authorities for them to delay publication for several years. But it differs from Alexievich’s books in that she almost never intersperses her narrative with an authorial comment, preferring to see herself as a historian of the “untraceable”, tracking not events but the feelings that people experienced during them, and reclaiming “the small, the personal and the specific”. Like the great Russian novels, these testimonials ring with emotional truth.

Moving memories … Svetlana Alexievich. Photograph: Maxim Malinovsky/AFP/Getty Images

It is no coincidence that most of her witnesses have been women. Alexievich, who began her writing life as a reporter on a local paper in Belarus, realised early on that what she was looking for, the memory of what things felt like, is better conveyed by women, who feel little shame in expressing an unvarnished sense of remembered horror. The death of beloved sons is a constant refr, as is that of suicide, about which she has also written a number of short storiesain that runs through her books. Embittered by wars in which they have been tricked into fighting, maimed by wounds that never heal, revolted by killings in which they were forced to take part, Alexievich’s male characters come home from war to take their own lives, leaving their desolate mothers to grieve anew. “They sent me back,” one woman says bleakly in Boys in Zinc, “a different man.”

Alexievich has refused to allow Soviet history to be written without the voices of people who endured the catastrophes

Perhaps not surprisingly, Alexievich was drawn to another relatively unchronicled “monstrous event”, the day in April 1986 when a series of blasts brought down the nuclear reactor at Chernobyl. Though its effects were felt everywhere from Israel to China, 70% of the radioactive fallout descended on Belarus, where rates of cancer soon increased 74-fold. Over a period of 20 years, Alexievich returned repeatedly to the area, to interview former workers at the plant, along with doctors, scientists, soldiers and peasants who had defied the ban and returned to their homes. The explosion, she writes in Chernobyl Prayer, was the “beginning of a new history” and at times it seemed to her “as if I was recording the future” (the writers of the recent HBO series drew on her book). Animals and insects had vanished and it had become a place of “possessions without owners … landscapes without people”, and the few who had returned to their poisoned homes had resumed earlier ways, reaping by sickle, mowing by scythes. Where once for the Belarusians catastrophe had been war, now it had become the toxic grass and earth, an enemy that no one could see.

Of all her books, her most ambitious, and at more than 700 pages her longest, is her most recent, Secondhand Time, published in English in 2016 and about the lives of people affected by the collapse of the Soviet Union. Alexievich wrote it during the 10 years she spent abroad in exile in France and Germany, having fallen out with the regime in Belarus in 2000. Based on interviews carried out over two decades, most of them with women, it deals with the years between Stalin’s death in 1953 and the assassination of the opposition activist Boris Nemtsov in 2015. Secondhand Time depicts a country in which people are poor and resentful and speak of the past, before perestroika, as the best and happiest time of their lives. When capitalism arrived to shatter their worlds into “dozens of colourful little pieces” and poverty became “shameful”, it confused them. Mikhail Gorbachev, one woman tells her, “opened the door of the cage and we made a run for it”. But freedom is not what they imagined, and in Putin’s “overcast, grey, brutal” regime they have found little to content them. “People have started believing in God again,” one man tells her, “because there is no other hope.”

Over almost half a century, Alexievich has recorded hundreds of monologues about what it is to be a human being, and for the most part a human being left behind. Given the speed with which memories alter and the way that perceptions of the past shift to reflect the mood of the present, they might have benefited from a little more context – the ages of the witnesses perhaps, or the dates of the interviews. But this is a small matter. What counts is that Alexievich has refused to allow Soviet history to be written without the voices of the people who endured the wars, calamities, famines, poverty and political persecutions that filled the 20th century. However grim and repetitive her books are, the cumulative effect, not least of Last Witnesses, is extremely powerful. This is for the most part because her own views – that war is atrocious, and that the poor, the powerless, minorities and dissidents, and even people who simply happen to be at the wrong place at the wrong time, are readily disposed of by those in power – are explicit in her choice of excerpts and the craft with which she shapes them. Few people have ever conjured better the pain of loss.

• Last Witnesses: Unchildlike Stories by Svetlana Alexievich, translated by Richard Pevear and Larissa Volokhonsky, is published by Penguin (£12.99). To order a copy go to guardianbookshop.com. Free UK p&p on all online orders over £15.

• This article was amended on 12 and 22 July 2019, to correct a reference to Ukraine that should have been Belarus, and to correct two instances where the book was misnamed “Lost Witnesses”.