Lean In: Women, Work, and the Will to Lead (2013) is a nonfiction book written by Facebook COO Sheryl Sandberg. Drawing on both research and her own experiences, Sandberg describes how and why gender inequality continues to operate in the modern workforce, and offers advice for women seeking to balance a career and family. Ultimately, Sandberg argues that full equality will only come about when women "lean in," pushing past their own fears and misgivings to demand equal opportunity and treatment.

Before launching into her argument, Sandberg sets the stage with an overview of women's status in both the United States and(to a lesser extent) the world at large. Despite considerable progress, Sandberg says, women remain largely excluded from the highest levels of government and industry. While this is in part the result of systemic barriers, Sandberg also feels that women unintentionally hold themselves back by absorbing sexist attitudes from the culture that surrounds them. Sandberg therefore claims that "reignit[ing] the revolution" requires "internalizing the revolution": letting go of biased and unhelpful beliefs (11).

In each chapter following the book’s introduction, Sandberg presents a sub-argument that feeds into this larger claim. Chapters One and Two deal particularly explicitly with the nature of the "internal barriers" women face: reluctance to pursue positions of power, and self-doubt that exacerbates this passivity and tentativeness. All of this, Sandberg argues, is a reflection of internalized gender norms rather than reality; women are neither less ambitious than men nor less capable, but they grow up in a world that encourages them to be agreeable and pretty rather than successful and intelligent. As a result, they don't learn the assertiveness and confidence they need in order to thrive in demanding career paths.

In Chapter Three, however, Sandberg acknowledges that it is not enough for women simply to resolve to be more assertive: because of the way society perceives gender, women who behave "like men" may face negative consequences. Nevertheless, Sandberg argues that it is possible for women to strike a successful balance, particularly if they are willing to be flexible with their career plans (Chapter Four) and open about their thoughts and feelings (Chapter Six). Having a mentor can also help, though Sandberg cautions women against becoming overly dependent on the help of others (Chapter Five).

In Chapters Seven, Eight, and Nine, Sandberg moves on to discuss strategies for balancing work and family life. Sandberg suggests that many of the problems women face in this regard are, again, the result of internalized biases: women hear that achieving both personal and professional success is impossible and alter their expectations in response, ultimately setting themselves up for failure. However, since it is true that women bear the brunt of housework and child care, Sandberg recommends that women be proactive about seeking support from their partners, as well as be willing to compromise on their goals when life becomes too overwhelming.

Sandberg wraps her argument up by urging women to speak out about gender inequality when they encounter it, and to support the choices their fellow women make. Returning to a claim she made near the beginning of Lean In, Sandberg says that when women finally achieve parity in the most powerful levels of society, they will put in place new, female-friendly policies to help ensure that "this next wave [of feminism] can be the last wave" (172).