Before I tell you how much I love Michelle Obama, let me tell you what I have against her. The former first lady is a woman capable of muddying your stance on things you stood firmly against. First on the list is the very concept of a first lady. Just think about this. For feminists, or anyone frankly with a 21st-century grasp of gender equality, it is a highly troublesome concept. It is a position that involves a woman – no matter the glorious complexity, glittering accomplishment or human drama of her prior life – being shoehorned into a role that is, by definition, about the man to whom she is married.

Her role has never been defined, because, I suspect, to do so would involve the awkward truth – that it’s essentially to make her husband look good. First ladies both feed into, and reflect, our patriarchal values, and so, in this world still so intolerant of female domination, making their husbands look good inevitably involves diminishing themselves, and a decoupling from their own achievements, so as not to outshine the president.

Obama is both the ultimate first lady and has also, which is the second issue, been folded into a narrative of the American dream. This is problematic from a black perspective because, as Malcolm X so pithily expressed it, “I don’t see any American dream. I see an American nightmare.” Obama’s role has been in the American dream of both the future, and the past. It’s often remarked that African Americans are the only Americans who do not have any “good ole days”. Because which period of American history could they be nostalgic for? The state sponsored terror of slavery, and segregation? The long, painful battle for civil rights? Or the enduring economic disadvantage and racism that all three left behind?

But it is precisely amid the dark chaos of these conundrums that we find the irresistible light of Michelle Obama. In Becoming – the first book that tells her story from her own perspective – she reveals that her life is a form of alchemy. Her childhood, growing up on the South Side of Chicago, is recalled with an essentially American kind of wholesomeness: a strong nuclear family of four, sharing a one-bed apartment upstairs while the one below was occupied by her piano teacher great aunt Robbie. Her family worked hard and kept things moving upwards.

If Obama were British, this would be a class tale. She describes herself in her early years as “the striver”. Later, campaigning for the first time with her husband, she recounts the moment she realised that her task is mainly to share this story with “people who despite the difference in skin colour reminded me of my family – postal workers who had bigger dreams just as [her grandfather] Dandy once had; civic-minded piano teachers like Robbie; stay-at-home moms who were active in the PTA like my mother; blue-collar workers who’d do anything for their families, just like my dad. I didn’t need to practice or use notes. I said only what I sincerely felt.”

The writer Ta-Nahesi Coates, present at one of these events, was so taken aback by her account of an “idyllic youth” that he “almost mistook her for white”, comparing her, he writes in his book We Were Eight Years in Power, to “an old stevedore hungering for the long-lost neighbourhood of yore”. “In all my years of watching black public figures,” he said, “I’d never heard one recall such an idyllic youth.”

In a book that takes a high moral ground, the political process is the only thing Obama allows herself to freely insult

But this protective love of Obama’s childhood did not shut out the communal sense of suffering and injustice that is, for any observer of America, impossible to avoid. The neighbourhood she grew up in was transformed by white flight, and later “deteriorated under the grind of poverty and gang violence”. An early experience with the police via her beloved brother Craig taught her that “the colour of our skin made us vulnerable.” Persistent experiences of discrimination bred in her family “a basic level of resentment and mistrust”.

Most of Obama’s narrative on race, however, comes courtesy not of her own perspective, but that of the many commentators who weaponised her blackness against her. “The rumours and slanted commentary always carried less than subtle messaging about race, meant to stir up the deepest and ugliest kind of fear within the voting public. Don’t let the black folks take over,” she writes. Obama recalls the “angry black woman” messaging, and the time “a sitting US congressman … made fun of my butt.”

But in its dignified tone, Becoming leaves out far more of this sordid history than it chooses to recall. The New Yorker magazine cover depicting her as an armed Black Panther, for example, the time Fox News ran an onscreen graphic describing her as Barack Obama’s “Baby Mama” – like the earlier “welfare queen” trope, a dog whistle appeal to the idea that, if the black family is at the root of America’s problems, how could one of them possibly be part of its solution? Or the time Fox host Bill O’Reilly said: “I don’t want to go on a lynching party against Michelle Obama unless there is evidence.”

Incidentally it is O’Reilly’s book that Obama will undoubtedly knock off the top of the bestseller list with Becoming – prompting him to tweet something vaguely gracious about the time she, in spite of his bile towards her, made the effort to seek out and be kind to his daughter at a party. It’s a gesture fully grounded in that most Michelle Obama-esque of doctrines. “When they go low, we go high.”

Becoming is a 400-page expansion of this essential doctrine, without compromising a refreshing level of honestly about what politics really did to her. I have read Barack Obama’s two books so far, and this is like inserting a missing piece of reality into the narrative of his dizzying journey. There are brilliant details from their love story, like the time she tried to set him up with other single women, only to discover he was just “too cerebral” for Happy Hour nights where single people would mingle. There are compelling insights into the sorrow of miscarriage, the loneliness of living with a man whose sense of purpose often left little room for anything else, prompting her to seek couples counselling lest their marriage fall apart.

“Coexisting with Barack’s strong sense of purpose – sleeping in the same bed with it, sitting at the breakfast table with it – was something to which I had to adjust,” she writes. Her candour about home life – the pressure of childcare, bills, debts, work and parenting – are interesting because they are so normal, and because normal is something she has never been allowed to be.

As the academic Ula Y Taylor has written, “the idea that a woman would have a ‘radical’ disposition simply by being a thoughtful working black mother says a lot about Americans perceptions of political spouses, and it helps us to better understand why Michelle Obama is perceived as too strong to be first lady.”

It’s hard to be cynical about either Obama’s strength of character or her authenticity. Her book confirms what was observable about her time in the White House, that while she may have had to shape herself into the mould of what politics requires of a first lady, it was still a first lady-shaped version of something real. Her genuine dislike for politics is hard to avoid, in a book rooted in a high moral ground above insults and mudslinging, the political process itself seems the only thing she allows herself to freely insult.

“The appeal of standing in an open gym or high school auditorium to hear lofty promises and platitudes never made much sense to me,” she writes. “The political world was no place for good people”, nothing but “the ugly red versus blue dynamic”, whose “nastiness” has affected her so personally. In this vein, she attempts to end the stubborn speculation about her own future candidacy. “Because people often ask, I’ll say it here, directly: I have no intention of running for office, ever.”

Michelle Obama and President Barack Obama ahead of Donald Trump’s inauguration in January 2017. Photograph: Bloomberg via Getty Images

It’s the one time you feel like you maybe know more about her than she knows herself. A few slights against politics and a one-sentence declaration that she will never run for office doesn’t quite cut it after so many pages of what is, unquestionably, a political book. It’s hard not to recall the time when, asked about the challenges of her husband’s political marathon, she once replied, “this is nothing compared to the history we come from”.

During Barack Obama’s tenure, it was Michelle Obama’s roots in the African American experience, in the history of the south that she understood innately as “knit into me”, that lent him crucial legitimacy among black voters. It resurfaces here, adding the profound warnings of past suffering to the observation that, as she sees the Trumps take over the White House, “the vibrant diversity … was gone, replaced by what felt like a dispiriting uniformity, the kind of overwhelmingly white and male tableau I’d encountered so many times”.

Becoming reads as Obama’s first intervention into this distressing new reality. It definitely does not read like it will be the last.

• Becoming is published by Viking. To order a copy for £15 (RRP £25) go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99.