The book, simply entitled Madeleine, gives Kate’s account, in her own words, of her daughter’s disappearance during a family holiday in Praia da Luz, Portugal, in May 2007, and the dramatic events that followed.

Four years after Madeleine’s disappearance, there is, sadly, still no prospect of an epilogue to the book anytime soon, answering that heart-rending mystery: Where is Maddie?

Anguish: Gerry and Kate McCann make an appeal for the safe return of their daughter, Madeleine

As the years have passed, the answer to that question seems more elusive than ever.

The trail seemed to go stone-cold long ago, and all new leads appear to be red herring after red herring.

Kate and Gerry McCann are desperate to reignite the search for their daughter, but where do they start?

With Kate’s book, it would seem. Close friends say the McCanns are pinning all their hopes on Kate’s story prompting someone, somewhere, to come forward with new information.

The aim of the book is two-fold: to put Madeleine’s disappearance back in the spotlight, and to raise funds so that the McCanns’ team of private investigators can continue their work in trying to find her.

Still missing: It is now almost four years since Maddie was abducted. Her family fear the case has gone cold

Reliving those first terrifying days after Madeleine vanished, and charting the dramatic events in the months that followed when even Kate and Gerry became suspects in their daughter’s disappearance, has been an intensely painful experience for Kate.

The tortured look that has been etched on the 42-year-old doctor’s face since Madeleine’s disappearance is still in evidence, and friends say she looks tired, thin and drawn.

Kate began writing the book five months ago on the computer in her study at the family home in Rothley, Leicestershire.

A family friend describes how she would write through the day, while the couple’s six-year-old twins, Sean and Amelie, were at school, and then return to her study to write late into the evening after the children had gone to bed.

She turned down the offer of a ghost writer because she wanted the book to be in her own words.

Pouring intense emotion into the book has given Kate a sense of focus, as well as renewed hope that Madeleine will be found.

Meeting publishing deadlines has also given Kate a feeling that she is doing something both positive and purposeful in her struggle to discover what has happened to her hazel-eyed daughter.

The McCanns hope sales of the book will raise more than £1million for Madeleine’s fund. The book’s  launch will be accompanied by several television interviews.

‘Nothing is more important to us than finding our little girl,’ Kate writes on the Find Madeleine website.

‘Our hope is that the book may prompt those who have relevant information (knowingly or not) to come forward and share it with our team.’

The publication of this book will propel the family back onto the world’s front pages and, as Kate herself remarks, they embark on this latest chapter in the Maddie story with very heavy hearts.

The McCanns’ fateful decision to leave Madeleine alone in a Portuguese holiday apartment with their then two-year-old twins, while they dined with friends at a nearby tapas bar, was one of the most controversial stories of the decade.

Criticised: Goncalo Amaral, the Policia Judiciaria inspector who led the investigation into Maddie's disappearence

There were even lingering suspicions, however unfair given that the allegations made against the couple have never been substantiated and the McCanns have been totally exonerated, that they had somehow been involved in their daughter’s disappearance.

But in the months that followed, the Portuguese policeman heading the investigation, Goncalo Amaral, became suspicious that the McCanns were somehow involved in their daughter’s disappearance. There were claims of inconsistencies in the couple’s account of what they did on the night in question, and criticism that Kate didn’t seem ‘emotional’ enough in the wake of what had happened.

Once subjective suspicion and groundless rumour were stripped away, however, Amaral’s ‘case’ against the McCanns was based almost entirely on the evidence of two springer spaniels.

When the police dogs barked after being let loose in the apartment from which Madeleine had gone missing, Amaral saw it as apparent confirmation that they had detected blood and ‘the scent of death’ at the apartment.

Amaral became convinced that Madeleine had died accidentally in the apartment, and that her parents had then staged an elaborate cover-up.

The couple were formally declared ‘arguidos’ — meaning suspects — in September 2007, four months after Madeleine’s disappearance. That ‘arguido’ status was lifted a year later.

But false suspicions about the McCanns had been stirred, and sadly opprobrium amongst some lingers to this day.

For these reasons, the launch of the book will be low-key. Kate will not be doing any signings because she has serious fears about being subjected to verbal abuse, or even physical attack.

The first of many: The McCanns give a statement to the media in Portugal in the days immediately after Maddie was abducted

‘Kate doesn’t want to give anyone the opportunity to have a go at her  during any promotional tour,’ a friend told the Mail. ‘Just writing the book has been emotional enough.’

As an example of the deep unpleasantness the McCanns have to deal with, you have to go no further than an organisation called The Madeleine Foundation, which has a website demanding answers from the McCanns to some 163 questions concerning the case.

The group, which comprises 28 members but claims it has thousands of supporters who have looked at the website, has already written to the McCanns’ publishers, Transworld, requesting answers to its 163 questions and is planning to step up its campaign to coincide with the publication of the book.

Around the time Kate McCann was finishing her book this week, the organisation was taking delivery of 10,000 leaflets entitled ‘What happened to Madeleine McCann: 50 facts about the case that the British media are not telling you.’

It now plans to distribute them to homes and shops across the country. The leaflet is divided into four sections: 1) Major contradictions in the statements of the McCanns and their friends. 2) The highly trained police dogs who detected the scent of a corpse. 3) Strange things the McCanns have said and done. 4) How the McCanns wasted public money on useless private detectives.

Crime scene: The bedroom from where Maddie was snatched

In 2009, 30,000 similar leaflets were distributed around the country — including Kate and Gerry’s home town — before the McCanns' lawyers, Carter-Ruck, obtained a High Court undertaking from the group’s secretary, retired solicitor Tony Bennett, to halt the leafleting.

He also agreed to stop sales of a book he had written, entitled What Really Happened To Madeleine McCann: 60 Reasons To Suggest She Was Not Abducted.

‘Many people subscribe to the view, to one degree or another, that we are not being told the whole truth,’ says Mr Bennett, seemingly oblivious to the pain he is causing the couple.

Just as cruel as The Madeleine Foundation are a number of internet sites established with the sole purpose, it would seem, of smearing the couple. Online comments from the public on such sites are often poisonous in the extreme — vitriol likely to intensify after the book goes on sale.

The McCanns have taken successful legal action to prevent the publication in Britain of Amaral’s book about the case, The Truth Of The Lie, in which he repeats his hypothesis that the McCanns were involved, but key extracts of the book are available online, fuelling the McCanns’ torment still further.

It has, of course, been impossible for Kate and Gerry to lead a normal life after all they have been through.

For the first few years after Madeleine disappeared, Kate was a virtual recluse. She gave up her part-time position as a GP at a practice in Melton Mowbray, closeting herself away in the family’s smart new-build home in a quiet cul-de-sac.

Feeling the strain: From the moment her daughter went missing, Kate McCann has been under constant pressure

She felt too depressed and anguished to venture far, and found it hard to deal with the stares she would get when she was out and about.

Over the past year or so, however, she has begun to circulate more often. Each morning, she prepares breakfast for the twins before seeing them off to their Roman Catholic primary school.

The school still holds a place for Madeleine, who was enrolled to become a pupil there in September 2007. Such details are a heart-breaking reminder of the little girl the McCanns have lost.

Once the twins are at school, Kate goes for a long run around the country lanes close by. At weekends, she is often seen out and about with the twins in the village, taking them to swimming and dancing lessons at a local leisure centre.

She also sets aside time twice a day to sit quietly in Madeleine’s bedroom, which friends say brings her comfort and solace. The twins sometimes play in the room, but it is off-limits to visitors.

Gerry, 41, works long hours as a heart specialist at a teaching hospital in Leicester, often cycling to work and back.

Most Sundays, the family walk together to Mass at their local Roman Catholic church, where prayers continue to be said for Madeleine’s safe return to her family.

Kate and Gerry do not socialise much these days, but remain close to their friends, David and Fiona Payne, who were part of the group dubbed the ‘Tapas Nine’ after they dined together on the night Madeleine vanished.

Friends say that Kate and Gerry remain close, although the agony of losing Madeleine has inevitably placed strains upon them.

In the past year, Kate has made a couple of trips alone back to Praia da Luz, staying with the local Anglican priest, Haynes Hubbard, and his wife, Susan, who have become close friends. Kate feels closer to her daughter there.

She and Gerry have been bitterly frustrated by the lack of progress made by private detectives.

One particularly inept Spanish outfit, Metodo 3, promised to have Madeleine home by Christmas. That was the Christmas of 2007.

Another detective, Kevin Halligen, is alleged to have conned the McCanns out of £300,000 and is currently fighting extradition to the U.S. on other fraud claims.

But the McCanns are said to be happy with their current team, led by former British police detectives Dave Edgar and Arthur Cowley.

Various individuals continue to emerge, claiming to know Madeleine’s whereabouts. In February, Marcellino Italiano, an Angolan-born nightclub bouncer, claimed she had been snatched by an Algarve-based paedophile ring which smuggled her into America.

To the McCanns’ intense frustration, the Madeleine police files have been officially abandoned.

The couple are calling for the case to be reopened, and have launched an online petition in support of that call, which they are asking supporters to sign. When they have 50,000 signatures on it, they will take their case to the Home Secretary.

For now, however, they are hoping Kate’s book will succeed where every other attempt to find Madeleine has not, prompting someone finally to come forward with the crucial piece of information that will unlock the mystery.

Screenshots of Comments from Armanda Leal: Mail 16-04-2011