Rarely does the suspect of a 77-year-old murder case become the lead story in every news bulletin and newspaper around the world. However, the announcement in January that a team led by a retired FBI investigator had discovered the man who betrayed Anne Frank and her family to the Nazis led to a sensational run of headlines, until a quick rebuttal by historians, and outraged protests by the suspect’s granddaughter, led to an equally swift climbdown and the withdrawal of the book that accompanied the investigation from some markets.

Over time, speculation about who betrayed Anne has reached the same fever pitch as conspiracy theories about who killed President Kennedy, but as I researched my own book, The Diary That Changed the World, I was astonished to discover the complicated history of a book that spurred court cases, lifelong feuds and murder threats, and drew in public figures as well known as Eleanor Roosevelt and Nelson Mandela, and as notorious as the North Korean dictator Kim Jong-il.

Anne has been portrayed as the ultimate victim of the Holocaust, an icon for adolescents around the war and a political pawn used by both sides in the Cold War, and has even been heralded by some US teachers as a bizarre sort of diet and fitness guru.

When Otto Frank unwrapped Anne’s diary with trembling hands and began to read the first pages in Amsterdam in late 1945, he could hardly have imagined that he would take his daughter’s teenage thoughts and experiences and mold them into one of the most influential and widely read books of the 20th century, The Diary of Anne Frank. Nor that he was opening himself, and her work, to scrutiny and controversy that would last for decades.

Seventy-five years after the first publication of the book I set out to discover why we still care so much about Anne, and how her remarkable father obsessively overcame every hurdle to ensure her lasting fame.

The Rise of Anne Frank

Otto must have felt he was handling a miracle when his friend and employee Miep Gies handed him the pages of the diary she had salvaged from the floor of the annex on the day that the family were betrayed and taken away by the Gestapo. What was amazing, however, was what Otto did next.

Almost immediately, he was seized by an unshakeable conviction that Anne’s diary was worthy of publication and had a message about our shared humanity that would change the world. In the beginning, few agreed with him. As he walked the streets of Amsterdam, carrying the diary in his briefcase, Otto would encounter old friends and tell them about his discovery. Not many believed that there would be interest in the musings of a teenager.

After corralling the help of a group of influential left-wing Dutch writers and publishers, Otto arranged the first publication of The Diary of Anne Frank in the Netherlands in 1947. A UK and German edition followed, but it was not until the American edition of the book was published in 1952 that the phenomenon of Anne Frank took off.

Almost immediately, Otto Frank was seized by an unshakeable conviction that Anne’s diary was worthy of publication and had a message about our shared humanity.

The Diary of Anne Frank has sold more than 31 million copies, been translated into 70 languages and been the subject of countless documentaries, feature films and television series. Nelson Mandela said it was one of the books he shared with his fellow inmates on Robben Island. He opened the Anne Frank Exhibition in Johannesburg in 1994.

Her story is still potent: an animated film, Where Is Anne Frank, by the Israeli director Ari Folman debuted at the Cannes Film Festival in 2021. In Amsterdam more than one million people visit the Anne Frank House every year, and millions more around the world have seen the touring exhibition.

To those who weary of her singular fame, it sometimes seems as if everyone who met Anne has written about their acquaintance, however fleeting. Far from slipping into history, more than seven decades after the first publication of the diary interest in Anne remains as strong, and as controversial, as ever.

The cold-case review in January, and subsequent book by the Canadian author Rosemary Sullivan, is one among many that seeks to answer the whodunnit aspect of the story. In reality, many people knew that the Jewish families were hiding in the attic at 263 Prinsengracht, and any of them could have betrayed the Franks.

A book that spurred court cases, lifelong feuds and murder threats, and drew in public figures as well known as Eleanor Roosevelt and Nelson Mandela, and as notorious as the North Korean dictator Kim Jong-il.

How The Diary of Anne Frank related to the bigger context of the Holocaust has been every bit as incendiary as the question of who betrayed the family. From the first reading, people opposed the publication of the diary.

In Amsterdam the influential Rabbi Hammelburg called Otto “sentimental and weak” and said all “thinking Jews in the Netherlands” should oppose the “commercial hullabaloo” of the diary and the Anne Frank House. And in 1997 Cynthia Ozick of The New Yorker said: “The diary has been bowdlerized, distorted, transmuted, reduced; it has been infantilized, Americanized, sentimentalized, falsified, kitschified, and, in fact, blatantly denied.”

The claim that Otto had sentimentalized the diary, at the expense of the family’s true Jewish heritage, would be at the center of a bitter 1950s court battle, then a lifelong feud, with Meyer Levin, an American writer who first championed the diary, but then fought Otto for a share of the proceeds from the highly successful play of the same name. At one point Levin threatened to shoot Otto, called him a tax dodger, compared him to a Nazi and enlisted Eleanor Roosevelt to speak out on his behalf. Otto himself said that he had never been so disappointed in a man in all of his life as he was in Meyer Levin.

At the same time, Otto was also forced to defend the diary’s authenticity in Germany, where Holocaust deniers brought a series of claims against him alleging that the diary was a fake that Otto had written himself. The Diary of Anne Frank was now at the heart of the battle over Holocaust denial, and controversy would rage for decades, exacerbated by the revelation in the 1980s that Otto had personally withheld five pages from publication. An unexpurgated publication of the diary in the 1990s prompted another round of soul-searching over Otto’s editing of the original script.

In Amsterdam, the influential Rabbi Hammelburg called Otto “sentimental and weak” and said all “thinking Jews in the Netherlands” should oppose the “commercial hullabaloo” of the diary.

Otto’s desire to share his daughter’s story embroiled him in years of legal battles, driving him to a nervous breakdown and eventually into leaving Amsterdam and seeking a new life in Switzerland. The popularity of the diary had turned Otto into a father figure for the world, and he spent his days overseeing every aspect of the publication and legacy of the diary from his home in Basel, and answering thousands of letters asking for his opinion, support and understanding. He had found happiness and love again with his second wife, Fritzi, who was also a Holocaust survivor, her daughter Eva, and Eva’s three children.

Yet Otto remained a remarkable, complex and haunted man. After his family had been killed by the Nazis, he was gripped by his belief in Anne’s diary, but that dedication overrode all else, and friends noted that in later life he rarely mentioned his other daughter, Margot.

In his stepdaughter Eva Schloss’s book, After Auschwitz, her daughters remember the happy family holidays they took with Otto and their grandmother, and how he told them stories and taught them to ride a bike and ice-skate — but also that visiting the house in Basel could make them feel uncomfortable. Eva’s daughter Sylvia said: “For weeks beforehand I dreaded the thought of having to stay in that flat. It was like a museum and I even called Basel a ‘ghost town’.” Otto often used Anne as an example when he spoke to the children, saying, “Anne would not have done that,” Eva said. “Occasionally he would even call one of the girls ‘Anne’.”

In Germany, Holocaust deniers brought a series of claims against Otto alleging that the diary was a fake that he had written himself.

Arguably Otto’s mission to spread awareness of Anne’s diary was, if anything, too successful. His work resulted in an unstoppable momentum and appetite for her story that turned the image of his daughter into a sometimes remote icon and exploited figure. Over the decades Anne’s name has been given to things as diverse as a rose, a refugee village in Germany and a Japanese tampon (in Japan the phrase “Anne’s day” is a euphemism for menstruation, after the candor with which she wrote about her first period).

Today, almost 80 years after Anne’s death, the battle to define what she means to the world is still intense, with the future of a multimillion-dollar industry at stake as competing foundations, cultural critics and former friends and relatives clash over the legacy of Anne Frank — and who should control it. In 2004 the North Korean dictator Kim Jong-il struck an agreement with the Anne Frank Foundation to publish the diary in the hermit kingdom. It is taught to all schoolchildren there today but they are encouraged to identify Anne’s struggle against the fascists with North Korea’s conflict with the West.

Are Anne’s words still meaningful to a young generation three times removed from the Holocaust of the 1940s? The director of the Anne Frank House in Amsterdam, Ronald Leopold, insists that in a world where so many young people are struggling to find and express their identities, Anne has never been more relevant.

“In April 1944 Anne wrote, ‘If only I could be myself I would be satisfied.’ She didn’t say, ‘I want to be a woman, I want to be Jewish, I want to be Dutch, or German,’ ” Leopold says. Anne shared a longing for the freedom to discover who she was, and in today’s culture wars that still connects with young people around the world.

Karen Bartlett is a journalist and the author of several books, including Architects of Death. Her latest, The Diary That Changed the World: The Remarkable Story of Otto Frank and the Diary of Anne Frank, is out now from Biteback