If nothing else, she wants to dispel the perception that a woman can't have it all and erase stereotypes in the workplace. One common theme in the book: As men advance, they are more liked. But as women make strides in an organization, they are less liked.
While her personal crusade has earned her much admiration, it has detractors. They reject what they deem the Superwoman ideal, especially one that comes from a C-suite mom who has the finances to afford child care and other amenities.
Sandberg sidestepped comment on critical pieces in The New York Times and London's Daily Mail that portrayed her as a rich elitist hopelessly out of touch with most women.
"There is a lively debate," she concedes. "Passions run deep, which is good. I'm simply worried about stagnation and apathy on this topic."
She also denied the book is a springboard to a run for political office, as some recent reports suggest. "Absolutely not."
Her message is simple: A deep cultural shift among men and women is needed just as much as a legislative one, based on Sandberg's anecdotes of lingering sexism from the halls of Silicon Valley to investment banks in Manhattan.
In one passage, she recounts how former House speaker Tip O'Neill said to her, "You're pretty. Are you a pom-pom girl?" In another, she describes an unnamed male executive who welcomed questions from other men during a dinner meeting but wouldn't allow women to join in.
Her own work experiences, and recent and even current data on women in Corporate America, led her and others to this conclusion: Despite progress from 1970 to the mid-1990s, the revolution has stalled.
To illustrate her point, Sandberg grabbed a yellow legal pad from a reporter and drew two lines flatter than a crushed ant — both depicting the "gains" women had made as CEOs and board members from 2002 to 2012. The percentages have hovered in the mid-teens, with little change.
"I believe the women's movement has stalled," says Gillibrand. "Sheryl is creating an organized effort … for women to be heard."
Sandberg is "not putting herself out on all women's issues — it's up to lawmakers to change the dynamics in Washington," says the first-term senator, who is sponsoring legislation for equal pay and improved child care. The two are friends and allies in furthering women's issues.
An Overachiever's Advice
Sandberg is a rare, overachieving exception in this testosterone-dominated corporate world: chief of staff at the Treasury Department by age 29; vice president at then-obscure start-up Google at 32; chief operating officer of Facebook.
Her fast-track career might even land her in the CEO seat at Facebook one day, if its current occupant, Zuckerberg, decides to focus on long-term product development as Bill Gates did at Microsoft. Such is the conventional wisdom in Silicon Valley circles.
"Lean In" amounts to a secondary job for Sandberg, who oversees daily operations at Facebook, which has annual revenue of $5.1 billion. But she has eagerly embraced this mission.
"There are several factors that contributed to the stalled revolution that started in the mid-1990s," says Shelley Correll, professor of sociology and director of the Clayman Institute for Gender Research at Stanford University. At Sandberg's invitation, she has spoken to Facebook employees about reducing gender bias.
"Workplaces haven't really changed, especially for women who are about to have children while they are in middle management," Correll says. "For just starting the conversation, she has done us all a favor."
This is not an overnight revelation for Sandberg, who first broached the topic in 2010 at the TED conference—an exclusive retreat for thought leaders—and again in a speech at Barnard College's graduation the following year.
The book is an outgrowth of her tireless work as an "organizer and activist" for a broad swath of women, says Gina Bianchini, CEO of social-networking service Mightybell and a longtime Sandberg friend.
"The true power of Sheryl is she brings together women of different backgrounds, interests and experiences," says Bianchini.
In a post on her Facebook page last month, Steinem said that "Lean In" "addresses internalized oppression, opposes the external barriers that create it, and urges women to support each other to fight both. It argues not only for women's equality in the workplace, but men's equality in home-care and child-rearing. Even its critics are making a deep if inadvertent point: Only in women is success viewed as a barrier to giving advice."
Finding 'the Right Balance'
Like her predecessors, Sandberg may inspire and irritate. She has legions in the tech community who idolize her—as well as inflamed concerns among detractors, who call her movement a top-down operation fueled by a personal fortune worth hundreds of millions on paper and a bully pulpit in Facebook, which has more than 1 billion members.
"You can have it all, by her definition, which is unrealistic," says Alexandra Levy, a former Google executive hired by Sandberg before Sandberg left for Facebook. "But I think she misses the fundamental issue about time management. There are only 24 hours in a day. How many hours do you want to spend with kids? Exercising? Running a huge company?"
"Life is about choices," says Levy, who is managing partner of Silicon Alley Media, a digital marketing and communications agency. "You can't do it all, but you can try to find the right balance. There is a reality and context to what you do."
Adds Doreen Bloch, CEO of personal-care site Poshly.com: "I don't question Sandberg's intentions or perspective. She is a marvelous leader, and I consider her a role model. I personally do not see value in buying the book because the concept is straightforward. Rather than read about climbing the corporate ladder, it's best to just get back to work."