SHE'S one half of the most powerful couple in the world, a history maker and trailblazer admired for her poise, smarts and glamour

But after reading a fascinating new book about her uneven life as the first African-American first lady of the United States, it's not much of a stretch to think that Michelle Obama might have been just as happy to remain an anonymous working mother in Chicago, enjoying a career as a respected healthcare executive, doting on her two girls and looking after a husband whose greatest aspiration was to become a law-school dean, as opposed to US president.

As Jodi Kantor, a respected political writer for The New York Times, makes clear in her riveting new tome, simply called The Obamas, the trajectory of Mrs Obama's life since her husband was elected president in 2008 has been anything but smooth sailing. It's been full of amazing opportunities and once-in-a-lifetime experiences that she could have only dreamed of as a youngster growing up in Chicago's working-class South Side -- but is the trade-off worth it when the nation tut-tuts about how dishevelled you look when doing something as simple as walking the family dog without full make-up?

The reaction to Kantor's work from the White House, and the First Lady herself, has been fierce -- even though the book's sources are close friends of the family and many former and current top aides. During a recent TV interview, Mrs Obama slammed the book for depicting her as an "angry black woman," but admitted that she hadn't actually read it.

But if she did, Mrs Obama, the great-great granddaughter of a slave, surely wouldn't be half as angry as she appears to be now. Kantor painstakingly -- and admiringly -- describes a woman who rose from a firmly working-class background, born to loving parents who stressed the importance of education and determination as the keys to future success.

Her father, Fraser Robinson III, was the personification of succeeding no matter what. Four years after marrying his wife Marian Robinson -- now the beloved "first grandmother" who lives with her daughter in the White House, helping to raise the two Obama girls -- Fraser was diagnosed with multiple sclerosis. But he insisted on being the main provider for his family, maintaining a job as a pump worker for the City of Chicago. (The first lady has an older brother, Craig, employed as the head basketball coach at Oregon State University.)

"The Robinsons kept his illness a secret from their children until they were teenagers, and he still went to his job at the city pump station every day," Kantor writes.

"They lived in a small apartment inside a house, where the Robinsons gave their children the sole bedroom and slept in the living room. Marian was a determined mother, volunteering at her children's school so she could keep an eye on their education.

"Fraser was stubborn, dignified and persistent. Later, he used to drive all the way from Chicago to Princeton (an Ivy League college in New Jersey) to see Craig play basketball, despite his disability. Once he stared in quiet dismay at the arena parking lot: it was gravel, meaning he could not traverse it in his wheelchair."

Fraser Robinson died in 1991. "Marian and her children had to make the decision to take him off life support," Kantor writes. "Barack was still just Michelle's boyfriend then, and he was far away in Cambridge, but he flew in to be by the family's side."

Michelle Robinson was a model daughter in every way -- a standout, thoughtful honours student, she graduated from Princeton University, and went on to earn a law degree from Harvard.

She met her future husband -- whose own family background presented even more obstacles to success, given the absence of his birth father -- in 1989 while they both worked at a Chicago law firm. Both were instantly smitten.

"Michelle had never kept boyfriends for long before. She was statuesque, impassioned, and loyal, with a wicked comedic glint," Kantor writes. "But she was tough on everyone around her, with expectations others often found unrealistically high, and few compunctions about calling people out when she felt they had failed. Those standards appealed to Barack. He wanted to live up to his potential, to hedge against the bitterness and disappointment of his father's life."

The couple married in 1992, and while Barack worked as a law professor and Chicago community organiser -- a job much derided by his Republican opponents -- Michelle joined the administration of Chicago Mayor Richard M Daley, of the famous Daley dynasty that has run the city for generations. She quickly discovered the dark side of politics, the horse-trading and back-room deals that get done to collect political chits useful for future electoral success, even if voters are poorly served as a result.

"She disapproved of how closely Daley held power, surrounding himself with three or four people who seemed to let few outsiders in ... She particularly resented the way power in Illinois was locked up generation after generation by a small group of families, all-white Irish Catholic -- the Daleys in Chicago, the Hyneses and Madigans statewide," Kantor writes.

Mrs Obama left the Daley administration after two years, disillusioned about politics, but soon after her husband surprised her with his desire to run for a newly open Illinois state senate seat.

Asked for her support, she replied, "I married you because you're cute and you're smart, but this is the dumbest thing you could have ever asked me to do."

He's been asking ever since. Barack Obama's rise in the political world has been nothing short of meteoric -- he went from lowly state senator in 1996 to American president-elect only 12 years later.

Michelle Obama has made plenty of sacrifices in the name of her husband's political career, and though it's been a sometimes bumpy road for her and the Obama girls, Malia, 13, and 10-year-old Sasha, Kantor's book makes it crystal clear that Mrs Obama is nothing less than a fully vested first lady who wields more influence over her husband than anyone, and greatly cares about the shared history they're creating as the once deeply segregated nation's first black occupants of the White House.

"She envisioned a White House that was inclusive, diverse, attractive and chic... she was also acutely aware that she and her family were the country's, and the world's, most important African-American role models.

"Changing stereotypes was part of why the Obamas had run in the first place, part of why she wanted everything to look as beautiful and refined as possible," Kantor writes.

What's one of the first things you do when your husband becomes the newly elected American president? For the shell-shocked Mrs Obama it was business as usual -- take your daughter to her tennis lesson at a public outdoor court in Chicago, garbed in baseball hat and dark glasses in an attempt to go undetected.

"Dazed by it all, almost as if reluctant to face the enormity of what had happened and what she would need to do, the president-elect's wife was clinging stubbornly to familiar routines: hence the tennis lesson," Kantor writes.

Though Mrs Obama briefly contemplated remaining in Chicago for the first few months of her husband's presidency so her girls could finish the school year, that notion was quickly nixed and the Obamas began the next phase of their lives.

His staff and hers have repeatedly clashed, Kantor's reporting reveals, but the president has consistently made it clear both privately and publicly that his wife can pretty much do no wrong. And, yes, he thinks she's still gorgeous to boot.

Kantor tells of one 2009 White House event: "For a few moments before ... he paused and relaxed. 'Hey, you look good,' he said to the first lady, eyeing her gray top and long strand of pearls. He slipped both arms around her waist and grinned: she gave him a small, satisfied smile.

"Staff members wondered if they should give the first couple a moment to themselves, but the audience on the other side of the door was waiting."

It's been a huge adjustment, living life under the White House spotlight, and the isolation for Mrs Obama has sometimes been intense. "The first lady was having an unhappy, difficult time in her role, several advisors said," Kantor writes of Mrs Obama's first year in Washington.

"Many of her fears had come true. She was far from the city where she had almost always lived and she had given up a life she'd spent a long time building. Some of her friendships had fallen apart: she was sensitive to any hint of exploitation, and some old friends had crossed the line, she felt, using her name to try and get jobs."

Though Mrs Obama chafes at the notion that she has led an unhappy life in the White House, all of her predecessors experienced a similar seismic shock to the system, going from relative anonymity to being the spouse of the world's most powerful leader, and all of the huge expectations that come with the role.

"The new first lady did not identify much with those who had filled the role before her, and she showed limited interest in studying their examples," Kantor writes.

"Outsiders sometimes compared her to Jackie Kennedy for their shared interest in beautiful clothing, or to Hillary Clinton, a fellow Ivy League-trained lawyer. But being compared to a socialite reared in boarding school seemed a bit absurd to the daughter of the South Side, and, unlike Clinton, she had no desire to wield power in the West Wing or hold elective office."

But life under the White House microscope was far from being all bad at the start. At first Mrs Obama was determined to showcase a chic and sophisticated African-American first family, but an unfortunate early mis-step was enlisting an interior decorator who had previously designed the office of a disgraced Wall Streeter with an $87,000 rug among other extravagances.

"Political advisors marvelled that the two women [the first lady and a since departed aide, Desiree Rodgers] had managed to pick, out of all the designers in the United States, the one guy whose work was at the center of a blow-up over Wall Street decadence," Kantor writes.

"The first lady protested that she was just trying to make the White House a comfortable place for her family: to establish a new home for her girls. The Bush-era carpets had stains from their pets."

Staffers also fretted about Mrs Obama's acceptance of an invitation to grace the cover of Vogue magazine in 2009. "The appearance had been the subject of some of the most uncomfortable exchanges her advisors could remember," Kantor reveals.

Mrs Obama is cognisant of her position as a role model to young African-American women, and she felt landing on the cover of the world's most famous fashion bible was a coup not to be turned down.

"There are young black women across this country and I want them to see a black woman on the cover of Vogue," she told her advisors, according to Kantor.

In her pre-first lady days Mrs Obama was a regular at the discount retailer Target, but she felt compelled to up her fashion game when moving to the White House.

"In general, her clothes made a lot of aides nervous. Just a few years before she had dressed like everyone else in Hyde Park, in cardigans and slacks from chain stores... as her husband became more successful, that changed fast," Kantor reports.

"Clothing became a compensatory measure for having to participate in his political life... Once she saw how she looked with top-flight clothes and styling, one friend said, there was no going back ... Looking fabulous gave her confidence, Michelle told others."

Though the White House pays for many of the first family's living expenses, holidays -- another favourite indulgence of Mrs Obama -- and personal parties aren't footed by the taxpayer.

The Obamas, while wealthy by most standards thanks mostly to the success of his two autobiographical books, still have financial worries, Kantor reveals.

"Behind the scenes, aides said, the Obamas were concerned about money: the president's books could only sell so many copies, and it would be years until he could write more and the first lady could write her own.

"From vacation rental homes big enough to accommodate the Secret Service to all the personal entertaining they did at the White House, their lifestyle had grown fiercely expensive."

Kantor doesn't suggest that the first lady is all style and no substance. Far from it.

"Whatever little structure the (first lady) role carried was dictated by a series of mandatory events," Kantor writes. "Laura Bush's staff had left her team with several large binders of instructions: how to order Christmas cards, pack for a foreign trip, organise the holiday tree lighting, and all the rest.

But in her own career, Michelle Obama just didn't do ceremonial events; she wanted strategy, impact, results."

Kantor's book details the first lady's desire to use her platform to make a difference in the lives of Americans, particularly children and US military families, and many of the more fascinating stories centre on how well she connects with her chosen audiences, and the confidence these encounters provide her with going forward.

But her number one priority? Being a hands-on mother to Malia and Sasha, who by all accounts are polite and well-adjusted girls... well, as much as young pre-teens can be when the likes of the Jonas Brothers perform a private concert for you, and Johnny Depp entertains you at a White House Halloween party.

One telling story -- and there are many -- in Kantor's book comes in the chapter titled "Malia's Great Escape". Life would never be the same for the youngsters after Obama's election -- even school concerts presented new challenges.

"As soon as the campaign was over the isolation of the presidency began to set in not just for Barack Obama but for the family," Kantor writes. "Michelle narrowed the circle Malia and Sasha were allowed to play with, other parents noticed.

"The girls got together with their closest friends but not with casual ones. When Malia's class gave a fifth grade band concert, the group performed the program twice: they played for parents and siblings in the usual venue... but because the president-elect could no longer attend school concerts without massive interruptions and distractions, the children played a separate concert to an audience of three -- Barack, Michelle and Sasha, who sat in a classroom."

Malia and Sasha's exposure to the media is tightly controlled, and anyone who breaks the rules is banished from future presidential access without question, Kantor writes. Modern technology is also mostly off-limits for the Obama girls.

While on a foreign trip Mrs Obama tried phoning her daughters but White House staffers couldn't locate them -- they were playing outside on the expansive lawns.

The staffers apologised to the Obamas, and made provisions to give the girls their own mobile phones to avoid such problems in the future.

"Michelle had to step in to say she wasn't ready for them to have their own phones," Kantor writes.

"Though Michelle Obama has no aspirations to carve a political career for herself a la Hillary Clinton, she's got her finger on the pulse of how her husband's West Wing operates and prods the president's staffers to effectively execute his ambitious agenda.

Her efforts have been a source of tension among some staffers -- nothing new there, as any first lady can attest to -- but Mrs Obama didn't come to Washington to fade into the woodwork, Kantor writes.

She disdains politics as usual, and urged her husband to fight for a massive healthcare bill two years ago against the advice of his former chief of staff because making health insurance more affordable and available was one of his top campaign promises -- though the bill has proven to be deeply unpopular among many Republicans and conservatives and is currently tied up in the courts.

The first lady has also encouraged her husband to speak up for immigration reform -- a deeply unpopular cause among many conservative Americans -- after meeting a young child whose parents are illegal immigrants. The divisive immigration issue -- and lack of any progress on the matter at all -- could haunt the president in November's presidential election, at least among Hispanic voters who were confident that he'd finally be the one to push through a bill that would address the status of the millions of undocumented in the country. Kantor's book ends in August of 2011, with a 50th birthday party that the first lady threw for her husband, featuring the likes of Jay-Z, Tom Hanks and other luminaries.

"Their debates with each other were probably never going to end," Kantor writes. "That was the nature of their relationship -- a friction-filled marriage that had proved strong nonetheless.

"But the presidency had united the Obamas like never before. Their own bond seemed not only intact but strengthened, their points of view closer than ever before."

They'll need all that and more come Election Day on November 6.

Kantor's book portrays a power couple more than ready to fight for their political beliefs, but for the Obamas, victory first and foremost begins behind the scenes.

As long as their union is strong and the girls are well adjusted they'll proceed onwards and, they hope, upwards. The evolution of Michelle Obama is far from over.

With a fierce election promised against likely Republican opponent Mitt Romney, she'll hit the campaign trail on behalf of her husband. A reluctant campaigner in the past, she's ready to go all out this time, Kantor says.

"In the fall of 2011 it suddenly seemed like she was everywhere: announcing a new hiring program for veterans, raising campaign funds," Kantor writes.

"Campaigning and fundraising was the only way she could finally fight back against the Republicans who she felt had blocked and humiliated her husband.

"After all, she was the most confrontational of the Obamas, the one who tended to slip into what one friend called 'mama bear' mode when her husband was threatened.

"This would be the last race he would ever run, and his wife intended for him to win."

- Debbie O'Dowd and Donal Lynch