RUTHFULLY YOURS

Mrs. Obama was raised on the South Side of Chicago in the mid-1960s into a bygone world of black, working-class aspiration. “I spent much of my childhood listening to the sound of striving,” she begins, referring to the struggling piano students taught by her exacting great aunt in the apartment below the one occupied by her father (a boiler attendant at a water-treatment plant), her homemaker mother, her older brother and her small self. The family, descended from South Carolina slaves, had come to Chicago as part of the Great Migration in the 1930s, though political and union leaders continued to deny black men entry to the city’s well-paid industrial jobs. Her aging great uncle, a former Pullman porter, insisted on his dignity, wearing suspenders, dress shirts and a fedora even when mowing the lawn.

A feisty child, as she readily confesses, Michelle learned to discipline her energies through the gentle nudges of her orderly and watchful parents. “My family was my world, the center of everything,” she explains. Holiday meals took place at her grandfather’s house two blocks away; there were family board games and trips to the drive-in as well as summer vacations at Dukes Happy Holiday Resort in western Michigan. “Leave It to Beaver” is what her Hawaiian-born, peripatetic future husband would call her childhood.

The Robinsons were fervent believers in the power of education to catapult their children from the grim African-American past to a more open future. They encouraged them to find answers to their questions in the family’s Encyclopaedia Britannica; they chided them for improper diction. “The idea was we were to transcend, to get ourselves further,” Mrs. Obama writes. And so they did: Michelle followed her brother to Princeton, then on to Harvard Law School and eventually to a posh Chicago law firm, where she would meet the man who would become the 44th president.

Mrs. Obama greeted each of her husband’s steps up the political ladder with a raised eyebrow. She was moved by his idealism but thought him “too earnest, too full of valiant plans” for the dirty dealing of Springfield, Ill., where he would serve as state senator, and Washington, where he would serve in the Senate and then, in an extraordinarily rapid ascent, enter the White House. Readers of “Becoming” won’t learn much about how the crafty outsider maneuvered his way into prominence in the “City of Big Shoulders” and the swamps of D.C. Here the blunt-speaking author plays the stereotypical adoring spouse. Indeed, some readers might greet her description of her husband’s “buoying faith that if you stuck to your principles, things would work out” with their own raised eyebrows.

In many respects, though, hers is a familiar sort of middle-class, quasi-egalitarian marriage. Her private trials—a miscarriage, IVF treatments, couples counseling—have already been trumpeted by a gossipy media. Always the striver, Mrs. Obama is up before dawn to make time for exercise before taking her girls to school; she multi-tasks her way between work, soccer practice and grocery shopping like a gym-toned Houdini. “Becoming” is not shy about the thrill of young love, or about the trade-offs and resentments of two strong and ambitious personalities, but, she concludes, “in life you control what you can.”

This combination of wise pragmatism, “mom-in-chief” authenticity and lively good humor makes Michelle a perfect foil for the aloof, brainy Barack, and it enlivens the many conventional passages of “Becoming.” Visits with Queen Elizabeth mix with daughter Sasha’s swim meets. When the family, along with her mother, moved into the White House, she instructed her daughters to continue making their own beds. (Her mother informed the White House butlers that she would be doing her own laundry.) It’s rare to see someone in politics enjoying herself as much as Mrs. Obama has seemed to. Even as the president’s approval ratings went south, her popularity soared. “Joe Public,” her husband sometimes called her. She remains one of the world’s most admired women.

Which makes it jarring when Mrs. Obama writes toward the end of her book of the indignities she suffered along with others “marginalized by race and gender.” “I knew invisibility. I’d lived invisibility,” she writes. Granted, she was not safe from racial animus. At Princeton, the mother of one of her white roommates demanded that her daughter be moved into a different suite, and during her White House years racial taunts periodically darkened the country’s growing love affair with its first black first lady.

But one lesson of her remarkable life is that the lingering effects of America’s racial history are no longer the central fact of black possibility. “I’d never been someone who dwelled on the more demoralizing parts of being African American,” she writes. “Optimism reigned in my family’s little apartment on Euclid Avenue.” Yes, optimism and the family values embodied by her parents’ devotion to her future. Mrs. Obama doesn’t talk much about the loss—since her own period of becoming—of families and communities like the one she was born into or of the chaotic homes and schools that have come in its wake. Which is a pity: “Becoming” might then have occasioned, alongside admiration, a renewed focus on the conditions that once encouraged everyday striving in places like Chicago’s South Side.

Ms. Hymowitz is the William E. Simon Fellow at the Manhattan Institute and the author, most recently, of “The New Brooklyn: What It Takes to Bring a City Back.”