A small boy with feathery blond hair stares out from the cover of Hattie Gordon's book. The grainy black and white photo captures a quizzical look in his innocent eyes.

It is an endearing picture, made all the more poignant when you read the accompanying synopsis.

He is the young Gareth Gordon. He made his first attempt at suicide when he was 13. He finally succeeded in taking his own life when he was 24.

Gareth's younger sister Hattie watched the tragedy unfold as it tore his family apart.

Her book, "the cafe after the pub after the funeral", is her attempt at making sense of the wreckage of her early years.

By rights, Hattie should have had an idyllic childhood. Her father, Giles, was a top literary agent, dealing with writers like Fay Weldon, Sue Townsend and Prince Charles. Her mother, Margaret, was an illustrator, best known for drawing the Wombles.

As well as Gareth, Hattie had another older brother, Callum.

On the surface, her early life was normal but that came to a shuddering halt when she was ten and Gareth, then 13, took an overdose.

From that moment, she lived in dread of what would happen next and there was no shortage of drama and tragedy in the family.

Her parents' marriage broke down and, at 13, she made her own secret attempt at suicide.

Hattie, 29, of Tidy Street, Brighton, recalls: "It was a gamble, not terribly serious. I did it at the same age as Gareth first tried and in some bizarre way it was like mimicry. I remember wanting to disappear and not quite equating that to death."

Another shattering blow was just around the corner.

When she was 15, her mother died of a rare muscle-degenerating disease.

Over the years Gareth made many more attempts at self-harm and suicide.

Somehow Hattie kept going. She did well at school and, after a spell travelling with Callum, went to Sussex University to study art history.

While she was there, Gareth finally took his life.

Hattie craved information, explanations, anything that would help her understand why her brother had been so hell bent on killing himself.

"There was never any clear diagnosis for Gareth. I wanted to try to make sense of it all."

She searched bookshops but found "nothing but psychobabble". She saw a bereavement counsellor from Cruse who helped enormously but still she felt she needed to piece together bits of a puzzle.

"I was in quite a state. I really thought I was going mad. I started grieving for my mother, which I had not done before probably because I was part of a family that just got on with things.

"My friends were amazing but I wanted literature that would somehow feed me during that time. I wanted to know about people who had come out the other side.

"I was vaguely interested in art therapy and knew you could free yourself through writing, so eventually I just started to write. I didn't necessarily think it would be a book but I thought I could sort out the chronology in my head."

She completed the first chapter and sent it to an agent, just as she was starting a new job in Chicago.

Two years later, she returned to Brighton and in-between working in a shop and training as a massage therapist, began to write.

She gathered reports from sometimes reluctant doctors, psychiatrists and specialists who treated Gareth.

Hattie's insistence on knowing the truth revealed some disturbing facts.

She found her mother's and Gareth's relationship described as a 'folie a deux' - a double insanity where two closely associated people experience a psychosis simultaneously.

She discovered it was her mother who gave Gareth the aspirins he used for his first overdose and razor blades.

The shocking revelations sent her mind reeling - did her mother think death would stop the pain?

Tucked away in the medical notes Hattie also found a handwritten letter from her mother.

It read: "The grisly ordeal just kept on and on. I found if I drank a fair amount at least it numbed the pain a little. I didn't know what to do. No one helped. No one advised. I couldn't eat and Gareth gave me no chance to sleep. I started to have fantasies about killing him. I thought if I could somehow get him to drink a bottle of whiskey I could quickly hit him over the head with a mallet we used for banging in the pegs when we went camping."

At that moment Hattie understood her mother - her desperation, confusion, the chaos of her mind, "not knowing if her life would ever be liveable without being held captive to her son."

Painful though it was, she gradually began to appreciate the dynamics of her family better.

She realised how little she had understood at the time, particularly about her mother and the mental and physical struggle she had endured, coping with a suicidal son and the pressure that put on her marriage.

Hattie's father was initially against the book. But when the book was published, he was proud of her.

His approval was made all the more poignant because two weeks after the book was published, he died, aged 63.

Initially Hattie worried the book might be depressing.

"But people have told me it is beautiful in places."

She has become involved with the Richmond Fellowship, a charity which supports people with mental health needs. She believes there should be much more dialogue on depression, mental illness and suicide.

She quotes a statistic she spotted on a tube train - according to the Samaritans, there are more people taking antidepressants (12 million) than voted in last year's final of Pop Idol (nine million).

She hopes the book will help to change attitudes to mental illness and those who take their own lives.

"Suicide is still taboo. People find it so hard to talk about it. I think it would have been easier if someone had said Gareth was mentally ill. And some of the confusion would have been easier if it had been discussed."

With so much pain behind her, Hattie could easily have gone under herself. Instead it has given her a determination to pack her life with good things.

She is looking to the future and has started her first novel.

"Now I feel like the rage I had before has settled inside me. It is laid to rest."

The Cafe After The Pub After The Funeral is published by Continuum Books. Some of the proceeds go to the Richmond Fellowship, www.richmondfellowship.org.uk