JK Rowling has told the Leveson Inquiry that she has had to take action against newspapers about 50 times over breaches of privacy and misreporting.
The author said journalists "drove her out" of the home she bought in 1997 with the advance from the first of her seven Harry Potter books.
She told the inquiry into press standards she felt like a "sitting duck" after a photograph was published of the house number and street name, and it became "untenable" to remain there.
Rowling described her anger when she found a note that a reporter had slipped inside the bag of her elder daughter when she was in her first year at primary school.
She recalled: "I unzipped her schoolbag in the evening, and among the usual letters from school and the debris that every child generates, I found an envelope and a letter addressed to me from a journalist. The letter said that he intended to ask a mother at the school to put this in my daughter's bag.
"I can only say that I felt such a sense of invasion. It is very difficult to say how angry I felt that my five-year-old daughter's school was no longer a place of complete security from journalists."
Earlier in the day, Sienna Miller told the inquiry she had accused her family and friends of selling stories to the media after journalists obtained intimate information about her by hacking her phone. The actress described how she felt "terrible" for even considering that those closest to her could betray her in this way.
And former Formula 1 boss Max Mosley recounted to the inquiry how he took the News of the World to court for its "sick Nazi orgy" story about him because he was so keen to "demonstrate they were liars".
He proceeded with the High Court action despite being warned it would cost him dearly and bring his private information back into the public domain, he said.
The inquiry heard that future witnesses will include former News of the World and Daily Mirror editor Piers Morgan and ex-News of the World chief reporter Neville Thurlbeck.
Rowling says the press complaints commission is "toothless".
"The PCC is toothless. It offers very little in the way of sanction to papers. it is a wrist slapping exercise at best."
"I am vehemently opposed to state control of media. But I do feel we need a body that has teeth."
JK Rowling has been handed a copy of an article in the Sunday Times that she has not seen before.
It is a piece published on the 14 August 2011 that claims that Rowling claimed to introduce "non-native" plants to her garden.
An exasperated Rowling says: "It's just ludicrous, I find it ludicrous. how is this...I do not recognize these plants I am going to plant."
"I thought they weren't going to run the article."
Rowling is speaking about an article in the Daily Express that claimed an unpleasant character in the Harry Potter books was based on her ex-husband.
She says it was not true and caused distress to her daughter whose biological father was Rowling's ex-husband.
"I said humorously the character was Gilderoy Lockhart was based on someone I had lived with briefly," she says. "That's true, but this person cant probably even remember we were flatmates."
She says the Express depicted her as the "kind of vindicate person who would use a best selling book to vilify someone".
"I had to sit down with my eldest daughter, talking about her biological father, and say this isn't true ... It was a horrible conversation to have to have."
Rowling says some parts of the British press seek retribution if people try to "lock horns" with them.
"A picture of my child was put in to the papers so very quickly after I asked them not to print my address, I thought that was spiteful."
Rowling says her desire to keep the precise address of her home secret is because she has some times been targeted by "unbalanced individuals".
She says she is not being "starry or precious" but on a number of occasions she has had to involve the police to deal with threats against her.
"I think its reasonable of me to wish the papers would refrain from making my whereabouts so very very identifiable," she says. "I have to live somewhere."
Rowling attacks the "outrageous" occasion when a journalist said her daughter had distressed pupils at her school by telling them Harry Potter died in the seventh book.
"My daughter was characterised as some sort of bully," she says. "There was not one word of truth of it."
"She could not have told anyone what happened in book seven because at her own request she did not want to know."
Rowling says that she has only put on a swimsuit in public twice since 1998, and both times photographs have been published.
"On the second occasion my guard was down, we' gone on holiday we hadn't encountered any press, I assumed wrongly...I forgot myself."
Rowling recalls a time when she got so worn down by the press attention she chased a photographer outside her house.
"I saw the photographer taking a photo from over the street," she says.
"I rather absurdly gave chase, how i thought I would outrun a 20-something paparazzo while pushing a buggy ... the cumulative effect becomes quite draining."
Rowling is speaking about a photograph that was taken of her daughter in swimsuit.
"Unlike an untruth that is in print that you can receive an apology when an image is disseminated it can spread about the world like a virus.
"That photo was on the internet months after the press complaints commission ruling.
She adds: "Given the fact an image has a life that cannot be recalled, when you have seen what someone looks like in their swimwear, an apology can not remove that."
Rowling says at one point two journalists from a Scottish tabloid took up residence outside her house in a car.
"I asked someone who worked for the PR company i employ to ask them what they wanted.
"The response they gave was 'it's a boring day at the office'."
She adds: "My family and I were under surveillance for their amusement."
Rowling says she was "completely trapped" in her house after the birth of who two youngest children.
"After the birth of each of my subsequent children for a week it was impossible to leave my house without being photographed," she says.
"On both of those occasions they took up permanent residence outside my house."
Rowling recalls how a journalist put a letter to her in her five year old daughter's bag while at school.
it remains my belief children do best when they are kept out of the public eye and their home life is secure and that means it feels like a place of safety
"I endeavored from the first to draw a clear line between what I considered warranted intrusion into my private life..."
"I had countless requests to be photographed with my daughter."
She says she thought that if she did not publicise her children the press would in turn leave them alone. Rowling says she thought there was an "unwritten code".
Rowling recalls how she was forced to leave her house in 1999 because it had become "untenable" to stay there due to press intrusion.
"A photograph had been published that showed not only the number of the house but the name of the street.
"I was a sitting duck for anyone wanting to find me."
Rowling says: "I believe very very strongly in freedom of the press."
"Alongside the kind of journalism we are going to be talking about today there is truly heroic journalism in Britain," she says.
"People literally risk their lives to expose the truth ... at the other end we have behaviour that is illegal and unjustifiably intrusive."
She adds: "I wonder why they are called the same thing."
Harry Potter author JK Rowling is now giving evidence.
Mosley says the stories about him had a devastating effect on his son who had a drug addiction.
"The News of the World story had the most devastating effect on him. He really couldn't bear it. For your son to see pictures of his father ... He went back on the drugs.
"Like many people on hard drugs it's extremely dangerous, you make a small mistake and you die. That's what he did."
Mosley says some journalists had "no human feeling at all".
Mosley says former News of the World editor Brooks and Daily Mail editor Paul Dacre launched a campaign against Mr Justice Eady.
Justice Eady adjudicated over the Mosley's privacy action against the News of the World.
Mosley says his reputation is forever tarnished by the NotW stories about him.
"Forever how long i live now that is the number one thing people think of when they hear my name," he says.
Mosley is addressing the nature of privacy.
"The problem is if you could breach privacy merely because you disapproved of what someone is doing or is not to your taste wed be all over the place," he says.
"Sexual behavior covers a huge variety and when you start analysing it what i might like someone else might hate...where would it stop?
"Provided its adults and provided it's in private and provided everyone consents then it's nobody else's business."
Mosley says it is not the job of the tabloid journalist to pillory people for their sexual tastes.
He says that if that were the case then many people, including the gay community "would be at risk".
Mosley says NotW reporter Neville Thurlbeck told the woman with secret camera that filmed him to "get him to do the Sieg Heil".
He says this shows the whole thing was a set up for the start.
|@ JoshHalliday : Max Mosley tells Leveson he has brought proceedings against Google in France and Germany and considering in California|
Mosley says he has told Google they should change how their engine works so results do not show the stories. But Google have said it is "not their job to police the web".
"Google could stop this material appearing," he says. "But they wont as a matter of principle."
Mosley says the "really dangerous things are the search engines" which point people to websites.
Mosley says he has litigation going on in 22 or 23 countries to remove the untrue stories about him from the internet.
|@ rosschawkins : Max Mosley at #leveson : Was told case would cost him a million if he lost but wanted to demonstrate his accusers were liars|
Mosley says he thought the News of the World article alleging he took part in a 'Nazi orgy' was outrageous.
"it was outrageous and illegal but the Nazi allegation was completely untrue," he says.
Lord Justice Leveson has revealed he expects former Daily Mirror editor Piers Morgan to appear at the inquiry.
Mosley tells the inquiry that Rebekah Brooks "could deny for England".
He says she and other senior News International executives "denied the 'For Neville' email, they denied they had more than one journalist involved in hacking, they denied it again until it become obvious...they kept denying."