A seventh-grade teacher at Pyle Middle School in Bethesda emailed me recently to say she'd referred to my linguistic research about male/female communication styles in one of her classes. After noticing that three girls in a row prefaced their comments with phrases like "I'm not sure about this, but... "or" this might not be right , but...,"she had voiced her concern that if girls continued to use such disclamers as adults in the workplace, they mightt not be taken seriously. She'd told the class about my research explaining that girls talk this way, as she put it, "to keep more of a community by downplaying difference in status, not making anyone feel stupid, etc. "At this, a student raised her hand and asked, "If girls care so much about community, why are we always getting in stupid fights?" The teacher was stumped. How should she respond?

I replied that girls' concern with community doesn't only require them to show they don't think they're better than others. It also leads to fights, because girls struggle to be included in their community, and against being excluded from it, every bit as earnestly as boys struggle for status within a group. I might instead have directed this teacher to Phyllis Chesler's new book, Woman's Inhumanity to Woman, with its thesis that girls and women often treat one another badly and that women's sexism can be harder to identify, describe and resist, because it often takes place behind the scenes.

"So what else is new?" you may be thinking. Girls' viciousness has been detailed in fiction (Margaret Atwood's Cat's Eye comes to mind) and nonfiction (Leora Tanenbaum's Slut!: Growing Up Female With a Bad Reputation, for which Chesler tells us she was interviewed, is especially eloquent). Chesler herself names 60 writers and researchers who have addressed the "shadow side of female-female relationships" in one way or another. Her own mother summed up the conventional wisdom that the women's movement was supposed to correct: "Don't trust women, they can be your worst enemy." What's new is the scope of Chesler's survey, both in the range of contexts she considers and the variety of sources she cites, her analysis of the origins of these dynamics in psychology and myth, and her impeccable feminist credentials: Her groundbreaking 1972 book, Women and Madness, is a classic of modern feminism.

Chesler worked for more than 20 years on Woman's Inhumanity to Woman, delaying its completion and publication while she wrote and published other books partly because she knew it would elicit accusations that she was reinforcing already endemic misogyny. But I'm glad she has completed this book. Women readers will recognize their own experiences in Chesler's examples -- not only what's been done to them (of which, Chesler found, most women are keenly aware), but also what they have done to other women (about which her interviewees were typically amnesiac).

While acknowledging that women's greatest suffering around the world and through time has been due to "manmade tragedies," Chesler aims to shed light on a "quieter war" and to encourage women to be more realistic in their expectations and more humane in their treatment of other women. A psychologist who characterizes herself, playfully, as a "lapsed Utopian," Chesler traces much of the energy (both positive and negative) in women's relationships to the complex, fraught and "mainly unconscious" mother-daughter relationship. Women have unrealistic expectations of selfless generosity from other women, whom they cast in the idealized mother role, and may react with irrational rage when it is not forthcoming.

Chesler seems to have read everything and thought deeply about it. In Woman's Inhumanity to Woman, she weaves together material from a multitude of sources, including research in a range of fields (including a few references to my own research); her own interviews with women; fairy tales and myths; memoirs, biographies and letters; popular and classical literature; current events; the writings of psychoanalytic therapists and theorists; the Babylonian Talmud; and sometimes searingly self-revealing personal experiences. (Among the more shocking and moving are the abuse she suffered at her own parents' hands, and being raped by a United Nations diplomat.) There are, throughout, delightful formulations. One of my favorites is, "They say: pity the mother of daughters; I say, pity the mother of a daughter who writes."

Along with social commentary and psychological insight, Chesler offers astute literary criticism, comparing accounts of the Electra myth in Sophocles' and Euripides' classical Greek plays, Eugene O'Neill's modern drama and Richard Strauss's operas. The Electra myth embodies Chesler's main themes: Electra forgives her father, Agamemnon, for sacrificing her sister Iphigenia as an offering to the gods, but cannot forgive her mother, Clytemnestra, for taking a lover and encouraging him to kill Agamemnon. Electra gets her brother Orestes to kill their mother. Thus, women usually target other women (or children) and use indirect rather than direct aggression. And Chesler's incisive intelligence supplies another layer of interpretation: Not only is Electra competing in Freudian fashion with her mother for her father, she is also competing with her father, siblings and mother's lover for her mother.

Chesler shows that although women are better than men in some ways (though this is not the topic of this book), there are also ways in which they are no better -- and ways in which they are worse. Although men are more often guilty of physical violence, women's tendency to use indirect aggression and to deny their competitive impulses can lead them to oppose each other in more destructive and wounding ways. Indirect aggression, for example, can take the form of shunning (suddenly a woman finds herself ostracized by her group without knowing why) or malicious gossip (though Chesler wisely notes that not all gossip is malicious). Even such clearly male violence as the "honor killing" of a female relative who is believed to have brought shame on the family can be instigated and impelled by the gossip of girls and women.

Many of Chesler's richest scenarios are drawn from the more than 500 interviews she conducted. But individual women's accounts of their experiences often left me wondering whether they were telling - - or were aware of -- the whole story. For example, in an illuminating chapter on women at work, Chesler quotes a head nurse who complains that the overworked nurses take their frustrations out on each other. "If you ask another nurse: 'where are the supplies?' either she won't answer you or she'll snap at you." Chesler is clearly right that many women feel freer to take out their frustrations on other women. But I thought back to some of my own interviews with female physicians. Some told me that nurses were sexist, refusing to help women doctors in ways they automatically helped the men. Others, however, told me that the nurses were their strongest support system; one said she had been saved from disaster more than once by a nurse. When I asked why her account differed from others', she said that women nurses did not react well to women physicians who behaved imperiously, as their male colleagues did, but became staunch allies with women doctors who treated them with respect and as peers. This supports Chesler's point that women at work are subject to a double standard. But I wondered whether the nurses who snapped at Chesler's interviewee were not also reacting in part to the way she addressed them.

Most of Chesler's examples have an unmistakable and heartbreaking ring of familiarity: the mother-in-law who blames her daughter-in- law, not her son, when he doesn't call or visit; the mother who is jealous of her daughter's success or her friends; the mother who prefers sons, exploits or incessantly criticizes her daughter, or beats and whips her children; the sycophantic "All About Eve"-like fan who seeks to replace and even destroy the famous woman to whom she has made herself indispensable; and the self-identified feminist who is no different from any of these women. But then suddenly you're in a land of pathology, with, for example, a mother who waits three months to call her daughter to acknowledge the death of the daughter's child, and six months to call when the same daughter loses her husband. More than once, I found myself wondering whether an interviewee was "all there" -- though this threw me right back to Chesler's powerful claim in Women and Madness that women are routinely labeled crazy when they respond in understandable or even inevitable ways to their second-class citizenship.

This is not a perfect book. It is too long and occasionally repetitive. Though they are all apt, Chesler's examples sometimes leave open the question of scale. For example, a divorce lawyer is quoted as saying that her women clients often fail to pay their bills, expecting the world -- and their lawyer -- to make up for their victimization. But how many women clients behave this way? What is the experience of other divorce lawyers? There are smaller frustrations as well. Excerpts from others' writing are presented without page references and sometimes without specific sourcing at all. References are grouped by chapter, so to find a reference (or a footnote), readers must flip pages back to recall what chapter they're in, then flip ahead to the right section of Notes or References. But these frustrations are not unique to this book and are a small price to pay for the author's analytic range, honesty and insights.

The accumulation of knowledge and understanding is always a process of error and correction. For so many years, men were idealized and women demonized. Then, a brief period saw the tendency to idealize women and demonize men. (Case in point: Chesler notes that many feminists, herself included, rushed to embrace the suicidal poet Sylvia Plath as the helpless victim of a faithless husband, but ignored the equally genuine likelihood that Plath could also be a victimizer.) The time has come to stop idealizing or demonizing either sex. As Chesler's irony-tinged title suggests, women should no longer be the silent partners implied, though hidden, in the word "man." Seeing women, like men, as capable of both courage and jealousy, of providing care and causing pain, is no more nor less than acknowledging women as fully human. Woman's Inhumanity to Woman is the perfect place to start confronting this truth.