The World Split Open: How the Modern Women's Movement Changed America.

• Author: Flanders, Laura

The World Split Open: How the Modern Women's Movement Changed America by Ruth Rosen Viking. $34.95. 480 pages.

Feminism has never had a single voice, strategy, or unifying tactic, but it has inspired people, and inspires them still, with the grand, radical notion that a baby should not have its future determined by its gender any more than by the weather.

That vision has motivated people to transform their society in dramatic ways (gaining women the right to vote or get an education) and in incremental, even symbolic, ways (like choosing your haircut or keeping your own last name).

Everyone, it seems, has her own definition of feminism. Here's mine: Feminism's not a group or a membership oath or an action plan. Like Marxism, it's a way of thinking: When you study power--who's got it and how it's used--you consider gender. Feminists taught us to look at power relations between people as well as between races or states; within families, as well as within worksites; in bed, in church, or in the movie studio, as well as on Capitol Hill.

The modern feminist movement has been a lightning rod. Organized reactionaries of the Pat Robertson ("feminists kill children ") school are quieter now than they once were, but in their place are media-friendly females who claim to oppose gender discrimination but aren't for equality, either. (I'm thinking of people like Linda Chavez, Ann Coulter, and Danielle Crittenden, who received lots of media attention for opposing the Violence Against Women Act, Anita Hill, and the Beijing Women's Conference.)

And within the women's movement, the debates have always been rollicking, though the media rarely covered them. Today, those debates rage on, as younger feminists continue to have bones to pick with their forebears.

Farrar, Straus & Giroux calls Manifesta "a powerful indictment from within the current state of feminism and a passionate call to arms." Authors Amy Richards and Jennifer Baumgardner met at Ms. magazine, where they worked alongside some of the luminaries of feminism's so-called Second Wave.

Savvy, conscientious, and ambitious, they represent, in many ways, exactly the bright, brash, and courageous heirs that the Steinem-era Second Wavers sought. But they're angry, too--if not at "feminism," then at a lot of feminists, particularly those who complain that young women "just don't get it."

Many young women do "get it," and Richards and Baumgardner know a lot of them.

In 1992, Richards helped to found Third...