FORTY four years ago, a girl was born into a poor family in Passaic, an industrial town on the skids in New Jersey. "The town was in the same situation as my family," says Harriet Rubin. "We were so poor, we were the furthermost you could get from royalty and we learned, pretty fast, that you had to figure out how to make your own way in life."

Harriet Rub in figured it out - and made her way to the top, where today she heads Currency, an imprint of Doubleday which specialises in bringing to business writing new disciplines such as philosophy and poetry. Next month, Bloomsbury publishes her own book The Princessa. Machiavelli For Women, a how to book for women who want to move into the fast lane and stay there. It is packed with ideas, advice, warnings and checklists and its exuberance will give food for thought to any woman who has had to face a challenge coming at her across the table - boardroom or kitchen.

The idea came to Rubin when she and two friends were sitting in the Palace Bar in San Francisco. It was 2 a.m. The piano player had long since departed, leaving three formidable women who, though all were capable of negotiating multi million dollar deals on behalf of others, couldn't face going home because their domestic lives were in a mess. Successful careerists though they were, they had got themselves into relationships in which they had relinquished control and ended up playing a game with rules imposed by someone else.

Harriet Rubin thought about all this and the result is The Princessa - a sort of Il Principe for women in which the princessa is counselled to take control of her life by treating it like a war.

"Everything is born in war," says Rubin, quoting Heraclitus. "Babies are born in a struggle. The first tulips of spring bear leaves sharp as knives to fight their way out of the half frozen earth. There is no shame in fighting."

The struggle is against the enemy, whether child, colleague, partner or self. The woman is a warrior who has to locate and then disarm the enemy. To do this, she has to develop a strategy (the why) and learn the tactics (the how) for achieving her goals. If the words seem militant it's because, she says, there is conflict in everything and the first law of the princessa is to become a woman who can fruitfully combine the apparently conflicting opposites within herself.

"Aspects of yourself that you think of as contradictory or as opposites are winning partners in war, she says. A princessa has to be a lover/fighter. One or the other is not enough.

The biggest obstacle to a woman bent on winning is that the rules have been made by men. So change the rules, disrupt the status quo, rearrange perceptions, Rubin sings out. Chaos favours women, because this is the time when boundaries shift and classifications crumble.

The Princessa is divided into three parts: The Book Of Strategy, The Book Of Tactics and The Book Of Subtle Weapons. The first includes advice on how to be disruptive, how to aim high, how to use tension.

"In the princessa's situation, normal rules do not apply. Obeying the law becomes a dangerous addiction ... In intimate war, the person who wields unfair ad vantage over you may be your mother, your boss, your spouse or lover, your child, the ghost of your own desires long denied ... You must love them and fight them at the same time. Obeying the rules is obeying their rules - and the worst thing you can do."

The second section gives advice on how to end a battle and deals with besting - which the author sets above winning: "Machiavelli's Il Principe could destroy his opponents ... but the princessa cannot cripple the enemy. She must make her opponent an Unwitting ally. This means neither: hurting nor eroding his confidence. Besting leaves the loser unhurt and inspired.

"Revenge is out, absolutely. It may give instant gratification but in the long run serves nobody." Prophetically - for she had not been unseated at the time of writing - Rubin cites Benazir Bhutto as such an example. Another diva who bit the dust, according to Rubin, is Hillary Clinton who misunderstood the power of power and tried to keep it all for herself. "If you try to control that which is not your own, you lose that which, is your own," she writes.

The final section looks at weapons. Not the usual weapons of guilt, lies, anger and cutting humour but the traits and qualities of the princessa's life - her aspirations, the story of her life so far and her unedited femininity.

It wasn't easy getting hold of Harriet Rubin. She was touring the US promoting the book and Bloomsbury was temporarily out of touch with her. Then, unexpectedly, she revealed herself for there, on the final page of her book is her e-mail address.

Overnight - and cutting through a few time zones - we were talking. The fact it was 6 a.m. in Los Angeles was no hindrance to this soft spoken, powerorientated woman and she talked happily about her role models: Joan of Arc, Golda Meir, Anna Akhmatova, Scheheradze, Rebecca West, George Eliot, the black slave Sojourner Truth, Dian Fossey, Cordelia, Margaret Thatcher. Wait a minute - Margaret Thatcher? Has she fallen into the trap of thinking that a person in power, who has stood firm, is to be celebrated not for what she does but simply because she is a woman? Lady Thatcher, the woman who had the most nurturing thing a woman can give withdrew it from her country's most vulnerable citizens children. But Harriet Rubin has already had second thoughts on this one: "I regret putting her in. If I ever have to revise the book, she comes out."

And then there's the question of tactics, of manoeuvring people, of getting them to do things. To many, this will confirm their prejudice that women are wily, scheming and out to get what they want. But on this, she holds her ground: "Why is it that when men go after what they want, they're described as strategists and when women do it they're said to be manipulative?"

A divorcee without children, she is now happily linked to Aram Miller, partner who taught her a lot about love and war. So too has Gandhi, who took his power from within himself.

"Here in America, we have a disease women suffer from called the empathy disease. They give in and give and give in until they have nothing left to give." There's no place for the sacrificial victim role in her book.

"Our deepest fear is not that we are inadequate. Our deepest fear is that we are powerful beyond measure ... We ask ourselves, `Who am I to be brilliant, gorgeous, talented and fabulous?' Actually, who are you not to be? Your playing small does not serve the world. There's nothing enlightened about shrinking so that other people won't feel insecure around you... As we are liberated from our fear, our presence automatically liberates others." That is the philosophy of "besting" - though the words are not the author's but taken, by her, from a speech by Nelson Mandela. Improve on it if you can.