With 10 million copies already sold, Michelle Obama's new book, Becoming, is on its way to becoming the best-selling memoir of all time. And probably no one is buying it because Obama's life is ordinary.

The former first lady was incredibly accomplished even before she married a future president and set an example of grace and dignity in the White House for eight years. But according to psychologist Ruthellen Josselson, who studies the life paths of women, the stages Obama went through mirror the life paths of ordinary women to a shocking degree.

"I've spent 45 years studying women's lives," she wrote on the Conversation recently. Obama, "despite living an extraordinary life, exemplifies the optimal path of development I found among my 'ordinary' women."

"Michelle titles her life chapters 'Becoming Me,' 'Becoming Us,' and 'Becoming More,' which map perfectly with the psychological stages of identity, intimacy, and care -- the eras I identified in women's lives," she argues. "Michelle Obama represents 'Everywoman.'"

1. Identity

Obama famously went from an ordinary, middle-class upbringing to great accomplishment. That path might be rare, but the process of figuring out who you want to become is the first stage in nearly all women's lives. And just like for many of us, it was a long and rocky road for Obama.

After working to become a high-powered lawyer, Obama was surprised to discover she actually didn't much like the career she'd chosen. "She felt empty practicing law," Josselson writes, so she switched to more  meaningful work at nonprofits. 

This kind of shakeup is surprisingly common. "Like Michelle Obama, women in my study often realized, in their 30s, that their initial choices were not what fit them," Josselson reports. "They could become judges or take on management roles. They could leave social work and become teachers for more family-friendly hours. They could, like Michelle, think seriously about what suited them and change course."

2. Intimacy

Once you have your identity sorted out, what's next? Love in all its forms comes along and confuses you once again. The intimate relationships we form often force us to rejig the identities we've worked so hard to develop. In her memoir, for example, Obama explains how her vision of a tight-knit family had to shift to accommodate her husband's political ambitions.

"Intimacy was leading her on a path she would never have chosen," explains Josselson. "Many of the women in my study followed similar trajectories, although, of course, on a smaller scale."

3. Care

The final stage for women is "care." And no, that doesn't mean every women's destiny is to become a mother. Instead, Josselson says, women generally evolve to see making the world a better place as their ultimate role in life.

"Once situated in the White House, which she partly regarded as a prison, Michelle sought to focus her energies and use her influence for a larger good," working on initiatives related to child health and serving as a role model for girls, Josselson writes. Again, this is a common turn in the lives of women, according to her research.

"Finding a way to care for others was central in the lives of the most fulfilled women I have studied. When these women reflect on the meaning of their lives at age 58, teachers describe students who returned to thank them for things they said that changed their lives. A doctor remembers working as a volunteer with AIDS patients," she says. "Those whose lives had the most meaning were those who felt they'd had impact on the lives of others."

"You find yourself by giving yourself away."

Is this three-stage development from unformed girl to a battle-tested identity to a focus on care universal? Of course not. Some women get stuck at the first stage and drift through life. But most women who end up fulfilled follow this process, according to Josselson.

Michelle Obama, in this one regard at least, is super ordinary. Her memoir makes clear she has learned a simple lesson over the course of her life, one that was neatly expressed by one of Josselson's study subjects: "You find yourself by giving yourself away."

The same appears to be true for all of us.