The 383-page German-language tome, which focuses on the designer's public and private life, has already caused a sensation in Germany after the publication of a passage that suggests that Lagerfeld's parents were members of the Nazi Party.

The book's author, Kaiser, was keen to make sense of Lagerfeld's carefully constructed public image, as well as debunking some popular German fashion myths.

They thought he was like a dandy, a decadent guy with too much money, and yet he did nothing. But as you know, he was a very hard worker," he explains.

And that's what I want to show too, that he worked with so many brands, with so much energy, and he was really a very good motivator,' he recalls. - He was a great boss. That's why a lot of people worked with him for a really long time.

In 13 months of research that began in March 2019, Kaiser conducted more than 100 interviews with classmates, friends, colleagues, business associates, neighbors and journalists.

And I talked to some of his relatives, which wasn't as easy as I thought it would be because a lot of them were a little bit offended by him because he spoke somewhat arrogantly about people from his past and some of his family members," Kaiser says.

Among them were Gordian Tork, grandson of Lagerfeld's aunt Felicitas Balmann, and Thomas Schulenburg, daughter of his half-sister Thea. Kaiser discovered many documents and photographs that shed new light on Lagerfeld's childhood in Bad Bramstedt, a small town about 25 miles north of Hamburg.

They moved to the village in 1934 when he was only a year old, and of course in the village they stood out because his father was rich -- he explains.

Otto Lagerfeld was a successful businessman who ran Glücksklee, a condensed milk manufacturer, and his mother Elisabeth was a former sales manager at a Hamburg department store with a strong sense of style.

I think my book really shows that Karl got his two main sources of his abilities from his mother on the one hand and his father on the other: business and style. Both of them came together in him because he was not only a great designer, but also, of course, a great businessman, -- Kaiser argues.

Among the letters sent by Elisabeth Lagerfeld to her sister Felicitas, now in Tork's possession, was a previously unseen five-page typed document titled "Why did I become a member of the N.S.D.A.P.?" -- the German acronym for the National Socialist German Workers' Party. Although the letter is unsigned, Kaiser believes it was Karl's mother who authored it, as she often typed her letters.

In the document, Elisabeth Lagerfeld explains how she was initially seduced by Adolf Hitler's promise to restore order and economic prosperity after the chaos at the end of World War I, but that she became disillusioned with the party when she saw Jews being rounded up for deportation in Hamburg. In 1941.

"She saw this and thought, 'This can't be true.'" And at that moment she realized that it was a bad ideology and that she didn't like it anymore. She stopped wearing party insignia. Although Kaiser notes that she did not give up her party membership for fear of reprisals.

After the war, Lagerfeld's mother stated in an official document that she had never been associated with the Nazis. Otto Lagerfeld, on the other hand, explained to the authorities that he had been a party member from 1933 to 1945 for the benefit of his company, a common practice among businessmen at the time.

Given the well-known historical context, Kaiser was surprised by the reaction to this revelation. The German tabloid Bild published an article Tuesday titled "His family's Nazi secret" along with a photo of Karl, then four years old, looking at the swastika flag his parents raised to mark the annexation of Austria in 1938.

There aren't many people in Germany who are as famous as he is, and so of course they say that, but in a way it's wrong because it suggests that it's a scandal. But it's not at all. Being a member of the Nazi party was a normal thing -- it's a truth about German history, -- Kaiser reasoned.

Lagerfeld himself often romanticized his childhood, though Kaiser says he doesn't know if the designer, who was 11 at the end of the war, was aware of his parents' political views. Unlike many other boys in his village, Lagerfeld did not belong to the Hitler Youth movement.

Most Germans really didn't talk about all this stuff after the war. That's why I think he probably didn't know what was going on during those years, and what's more, he said his parents didn't talk to him about politics -- he says.

Pierpaolo Righi, chief executive of the Karl Lagerfeld brand, says that despite the buzz, Kaiser's book will be a comprehensive account of Lagerfeld's life.

I really think it's probably one of the most versatile books, if not the most versatile book I've read about Karl -- he says -- The book really captures Karl's life, his personality and his work well, and it's really inspiring to read and gives people a lot of context, different perspectives. It reveals things they haven't heard about, but not in a sensationalized way. She wrote to really get to know Carl better.

Reflecting on Lagerfeld's sharp mind and even sharper language, Kaiser believes the designer was shaped by his extremely demanding mother and the experience of being bullied at school as a teenager.

Elisabeth Lagerfeld was a very strict person, very tough, very demanding of her son. But for him, it was not only frustrating but also a strong motivation.

He devotes an entire chapter called Demütigung ("Humiliation") to Lagerfeld's school years. A loner who preferred sketching to playing sports, he was bullied by other boys who instinctively rejected his fine clothes and aristocratic manners.

He was a "good" boy. That means he wasn't like the others, which means he was gay. I don't think there were words to describe it in those days. He always said his mother was very liberal about it and didn't care," Kaiser explains.

But of course he faced resentment, hatred, harassment from the other boys," he adds.

I think it really affected his personality as he tried to put on a mask so he wouldn't be bullied anymore. It's a bit of a paradox, since the mask he developed over decades made him famous. But it was like a shield.

Kaiser did not solve the mystery of why Lagerfeld, upon arriving in Paris, said he was less years old than he really was. He was shortening himself by five years. The author notes that Raphaele Bakke, who published a French biography of Lagerfeld last year, believes it was because of competition with the younger Yves Saint Laurent.

He, on the other hand, thinks it may have something to do with Germany's Nazi past.

I heard him once say: "I was born in a terrible year," meaning 1933, because that was the year the Nazis came to power," Kaiser says. "It's impossible to prove, but it's probably one of the reasons why he took five years off his age and said he was born in 1938.