As problems pile up for Hillary Clinton's presidential campaign, the former First Lady is set to be hit by an 'October Surprise' from one of her fiercest critics.

Author Ed Klein, who has already written three virulently anti-Clinton books, has a new book due out on October 4, just five weeks before America goes to the polls.

And with the title, Guilty As Sin, superimposed in prison-like bars over an unflattering picture of the Democratic presidential nominee, it is clear Klein's book will pull no punches.

Ed Klein's new Hillary Clinton book, Guilty as Sin, will focus on the personal email server that Clinton set up in her home in Chappaqua, New York

In publicity material, Klein says Guilty As Sin 'uncovers the real story behind Hillary's email scandals and the dirty political games that have kept her one step ahead of the law - for now'

Clinton had appeared to be sailing toward the White House due to repeated gaffes from her Republican opponent Donald Trump, but in the past week her campaign has stalled after being hit by scandals surrounding her family's charity, the Clinton Foundation, and allegations that she has serious health problems.

But Klein, 79, says the new book will focus mainly on the personal email server that Clinton set up in her home in Chappaqua, New York.

In publicity material, Klein says Guilty As Sin 'uncovers the real story behind Clinton's email scandals and the dirty political games that have kept her one step ahead of the law - for now'.

He also says the book will show how a Congressional investigation is finding 'new shocking evidence of corruption on a level some would call treason'.

And he says it will reveal 'what Bill and Hillary still have left in their bag of tricks in their desperate quest to get back into the Oval Office'.

Klein started his book campaign against Clinton back in 2005 when he wrote The Truth About Hillary, a book that was subtitled 'What She Knew, When She Knew It And How Far She'll Go To Be President'.

He followed that up with Blood Feud, which purported to reveal a schism between the Clinton and Obama families in 2014 and the following year he wrote Unlikeable: The Problem With Hillary.

But his no-holds-barred approach to Clinton has earned him many critics - even among Republicans.

Klein's Blood Feud purported to reveal that there was a rift between the Clinton and Obama families in 2014

Blood Feud was full of thinly sourced tales of tension between Bill and Hillary Clinton on one side and Barack and Michelle Obama on the other

When reviewing The Truth About Hillary, conservative columnist John Podhoretz called it 'one of the most sordid volumes I've ever waded through'.

'Thirty pages into it, I wanted to take a shower,' Podhoretz added. 'Sixty pages into it, I wanted to be decontaminated. And 200 pages into it, I wanted someone to drive stakes through my eyes so I wouldn't have to suffer through another word.'

The book included the allegation that Chelsea Clinton had been conceived after Bill had forced Hillary into sex during a 1979 vacation at the Horizons resort in Bermuda.

It quoted the future president as drunkenly telling a group of men he had met in the bar: 'I'm going back to my cottage to rape my wife,' and then quoted one of the men - identified as 'an investment banker from New York' - as saying the following morning their room 'looked like World War III', with 'pillows and busted-up furniture all over the place'.

'Obviously Hillary's got pissed off at Bill, and threw a few things across the room,' the unidentified banker allegedly said. 'I guess that's the price he paid for going back to his room and taking the initiative and demanding sex.'

The book then claimed that Bill found out he was to be a father after Hillary threw a press conference and announced she was pregnant, and that he had told long-time lover Dolly Kyle Browning that he only wanted a child because it would help him politically.

Klein's The Truth About Hillary discussed what he claimed was a tumultuous relationship between Bill and Hillary Clinton

Klein claimed in one book that Chelsea Clinton had been conceived after Bill had forced Hillary into sex during a 1979 vacation at the Horizons resort in Bermuda (pictured)

Hillary Clinton's spokesman said the book was 'full of blatant and vicious fabrications contrived by someone who writes trash for cash'.

James Geraghty wrote in National Review: 'Folks, there are plenty of arguments against Hillary Clinton, her policies, her views, her proposals, and her philosophies. This stuff ain't it. Nobody on the right, left, or center ought to stoop to this level.'

When Blood Feud came out, it was full of tales of tension between Bill and Hillary Clinton on one side and Barack and Michelle Obama on the other. Klein was again accused of making stories up.

The very first anecdote in the book was about a lunch at Le Jardin du Roi, a restaurant in Chappaqua, and quoted the restaurant's owner as being called Roi.

The restaurant's name is actually French for The Garden of the King and its owner is named Joe Quartararo.

Glenn Beck's website The Blaze said Blood Feud included some 'striking revelations' - but warned readers that Klein claimed the book was based on 'dozens and dozens of interviews' with those close to both First Families, noting none of the alleged sources were identified.

The very first anecdote in Blood Feud was about a lunch at Le Jardin du Roi (pictured), a restaurant in Chappaqua, New York, and quoted the restaurant's owner as being called Roi

The restaurant's name is actually French for The Garden of the King and its owner is named Joe Quartararo (pictured)

'We would advise given the nature of the material alone that everything be taken with a grain of salt,' The Blaze wrote.

Blood Feud claimed Clinton, as Secretary of State, had one argument with Obama when she poked him in the chest. 'It hurt,' Obama allegedly said.

The book also claimed that the health issues that forced Clinton to postpone testifying to the House committee investigating the attack on the US consulate in Benghazi, Libya, were far more serious than she admitted.

She claimed she had a stomach virus but Klein said it was due to a blood clot on her brain and that 'her heart valves were not pumping in a steady way'.

In Unlikeable, Klein claimed Clinton had attacked Obama over the investigation into her email server.

'What I want for you to do is call off your f***ing dogs, Barack!' she supposedly told the president during a White House meeting, breaking protocol by not calling him 'Mr. President'.

Clinton's health has been questioned in recent weeks after Right-wing websites circulated an old picture of Hillary Clinton slipping while walking up a flight of stairs (pictured)

Obama then supposedly responded, 'There is nothing I can do for you one way or another. Things have been set in motion, and I can't and won't interfere. Your problems are, frankly, of your own making. If you had been honest…'

Unlikeable also focused on Clinton's health problems, which have gained traction in recent weeks.

Klein said Hillary is frequently plagued by blinding headaches, and quoted another unidentified friend as saying: 'For the first time since I've known her, she's showing self-doubt about her strength and vitality.'

Clinton's spokesman Nick Merrill told the New York Post: 'Someone should do a book about Ed. They could call it "Bulls–t: The Problem with Anything Ed Klein Writes".'

'The only true thing about him is his consistent and utter lack of a relationship with the facts,' Merrill added. 'He has more hair than credibility, and the man is bald.'

Klein declined to speak to DailyMail.com, referring us to his publishers, Regnery. The company's Caitlyn Reuss said Klein is still finishing up his manuscript and his reporting is 'going to make waves.'



