Found in the 1980s, the "Hitler Diaries" were one of the most infamous cases of forgery in history. Who actually wrote them?

German forger Konrad Kujau

https://www.britannica.com/topic/Hitler-Diaries

Serial forger and con artist Konrad Kujau sold sixty volumes of a diary purportedly written by Hitler and supposedly found tucked away in a barn to 'Stern' magazine for $3.4 million 1983 dollars. Rupert Murdoch's London 'Sunday Times' ($1 million) was among other publications that were also duped. The diaries were proved to be fake within two weeks.

The ensuing scandal was the downfall of several journalists and the perpetrators of the fraud were jailed.

Just goes to show that lazy fact-checking and fake news are not modern phenomena.

https://www.britannica.com/topic/Hitler-Diaries
https://hoaxes.org/archive/permalink/the_hitler_diaries

Shortly after the so-called Hitler Diaries were exposed as a hoax 35 years ago this Sunday, The Sunday Times, the newspaper which had believed them genuine and published extracts, excused itself with the lofty observation: "Serious journalism is a high-risk enterprise."

The newspaper's Australian proprietor Rupert Murdoch was slightly more down-to-earth. "We're in the entertainment business," he is supposed to have shrugged.

https://www.independent.co.uk/news/uk/home-news/hitler-diaries-anniversary-sunday-times-extracts-hoax-fake-news-germany-a8337286.html

I highly recommend the film "Schtonk!". It is not a documentary of what happened, but a satire of the events and the spirit of the times that made them possible.

https://en.wikipedia.org/wiki/Schtonk!