The glass ceiling—the once ubiquitous metaphor referring to a subtle barrier built upon biases that block women from the highest positions of leadership—doesn't apply today, a book released earlier this year contends.

The book is titled "Through the Labyrinth: the Truth about How Women Become Leaders" and was co-written by Alice Eagly, professor and chair of psychology in the Weinberg College of Arts and Sciences at Northwestern University, in Chicago, and Linda L. Carli.

It draws upon a range of research from economics, political science, psychology, and anthropology to offer a picture of how far women have come in recent decades and how far they have to go, from the authors' perspective, to achieve equality. It outlines conditions that differ considerably from those of glass-ceiling days, and provides guidance for overcoming challenges.

Labyrinth, as the book title suggests, is a more apt metaphor than glass ceiling for describing the various challenges that women encounter as they navigate complex and often discontinuous paths toward leadership, the authors say.

Eagly and Carli present the point of view that despite significant strides women have made in leadership, the subtle as well as blatant barriers that they face today result in a progressive loss of women at all career stages, ultimately affecting the number who are even within reach of powerful positions.

"There isn't an absolute barrier stopping progress at a high level but rather a progressive falling away of women at every level, not just at the top," says Eagly, who has done extensive research on women as leaders.

Among the issues the book covers are various types of discrimination that the authors believe women leaders face, the psychology underlying the prejudices, reactions to women's leadership behaviors compared with men's, and the evolving division of labor at home.

A number of higher-level professional jobs, for example, have become extreme jobs, requiring far more than 40 hours of work per week.

"Those who put in longer hours generally rise faster, making it very difficult for people with family responsibilities, who are disproportionately women," Eagly says.

Another issue is the double bind that women face when it comes to leadership behavior.

"The research shows that when a woman is assertive and takes charge, people often react negatively, but if she fulfills the prescribed stereotype of a kind and gentle woman, she may be regarded as a poor leader," Eagly says.

Among the book's suggestions, women are advised to blend culturally masculine behavior with the positive aspects of feminine behavior.

"In some extremely masculine organizations, feminine warmth may not be welcomed, but in general many women leaders who are successful engage this blend of behaviors," Eagly says.

To rise in an organization, the book stresses, women also need to do a better job at building social capital by expanding their social networks beyond narrow confines of their jobs. Research shows that employees who have good relationships with colleagues both inside and outside of their own organization rise faster than those who focus more narrowly on traditional managerial tasks.

The good news for women is that the power elite in the U.S. looks a lot more like America than it did in the past, Eagly points out. Prime examples of contemporary women who didn't run up against a glass ceiling include U.S. Secretary of State Condoleezza Rice, Speaker of the U.S. House of Representatives Nancy Pelosi, and Harvard President Drew Gilpin Faust.

About 23 percent of chief executives of all organizations, as well as presidents of colleges and universities in the U.S., are women. Yet, until the 1980s few women were allowed to begin careers that would lead to top positions, the book asserts.

Amid enormous social change, women have gained access to most lower- and mid-level positions, now constituting a majority of managers in many areas, with the greatest concentrations in medical and health services (68 percent), human resources (66 percent), social and community services (66 percent), and education (64 percent).

Still, women don't have nearly as much power and authority as men do, the authors' research shows. Even when male and female managers are in comparable positions, women tend to wield less authority over others than men. The positions women hold generally confer less power to make decisions and to determine others' wages, the book says.

The continuing reports of "the first woman" to hold a prominent position show that while a few women are negotiating the labyrinth to top leadership positions, equality remains a distant goal, the book contends. Of the most highly paid officers in Fortune 500 companies—with titles such as chairman, president, chief operating officer, and chief executive officer—only 6 percent are women. Most notably, only 3 percent of Fortune 500 CEOs are women.

Besides the small number of women in the corporate elite, many of their positions are peripheral to the centers of power. For example, women are concentrated in staff-management positions rather than line-management positions that involve direct responsibility for corporations' bottom lines, the book says.

It concludes that organizations need to leverage underutilized talent and can't afford to exclude women from leadership positions. To show the gains that women leaders can bring, Eagly points to an analysis she compiled showing that women do a little better than men in delivering the kinds of style that work best for managing a contemporary work force. Specifically, women are more likely to be leaders who communicate the importance of an organization's mission and mentor, empower, and encourage those they lead, the authors argue.

"As the labyrinth implies, a woman's route to a leadership role can be challenging," Eagly says. "By employing scientific evidence to tackle the question of why it is more difficult for women to advance and offering the best answers available, we hope to inspire thoughtful strategies for both women and the organizations that employ them."