"Spare" is the name of the book that led to headlines in the English press during the day.
The book was released in Spain on Thursday and the Reuters news agency has read it.
One of the more sensational pieces of information in the book concerns how his brother Crown Prince William knocked him to the ground as recently as 2019.
The brothers reportedly fell out after William called Harry's wife Meghan Markle "difficult" and "rude".
Tried drugs
The argument escalated to the point where William grabbed Harry by the collar and knocked him down.
Everything is based on Harry's own words and the British royal house has chosen not to comment on the information.
In the book, Prince Harry also talks about how he tried cocaine as a 17-year-old, but that it was not for him.
In one chapter, the prince, who served as a helicopter pilot in the war in Afghanistan, writes that he killed 25 people.
In total, he is said to have completed six missions and he shows no remorse for participating in the killing, but no pride either.
Previous criticism
“When I was in the heat and confusion of battle, I did not think of the 25 as human beings.
They were chess pieces removed from the board, bad people eliminated before they had the opportunity to kill good people," he writes according to Reuters.
Excerpts from the book have caused a stir in the media.
As recently as a month ago, Prince Harry and wife Meghan were in the limelight after their documentary series premiered on Netflix.
There they were strongly critical of how they were treated by people within the British royal house.