(FORTUNE Magazine) – The American divorce rate keeps rising, and yet we hear less than we used to about certain themes long associated with divorce. We are less likely to hear the word ''alimony,'' for example. Nor is the public often treated to courtroom charges of adultery and cruelty. What has changed everything is ''no fault'' divorce, now essentially the law of the land. In every state except South Dakota, it is now possible to end a marriage without supplying a reason; in many states, furthermore, one spouse can call it quits without the consent of the other. The surprising, often depressing consequences of these changes are expertly elaborated in The Divorce Revolution (Free Press, $19.95), by Lenore J. Weitzman, associate professor of sociology at Stanford. No-fault divorce, initiated in California in 1970, was widely viewed as a welcome reform. It had always been possible, of course, for the partners in an unhappy marriage to agree to go their own ways. However, the law generally assumed that any division of their property must reflect the share of guilt attributed to each partner. ''I remember this horrible grind we went through to prepare cases under the old law,'' one lawyer told Weitzman, referring to the sham and perjury, the use of private detectives, neighbors on the stand, even children testifying about the delinquencies of their parents. Was all this pain and suffering really necessary? California's legislators listened to family law experts and concluded that it was not. Weitzman started out thinking that the experts were obviously right. ''When I initiated this research,'' she says, ''I assumed, in the optimistic spirit of the reformers, that . . . no-fault divorce could only have positive results.'' For example, it would treat women as equals. ''The no-fault divorce law promised the abolition of all sexist, gender-based rules that failed to treat wives as equals in the marital partnership.'' A major finding of The Divorce Revolution is that equal treatment has had perverse consequences for women. While the book's examples and data are largely drawn from California, its generalizations tend to inspire confidence. Weitzman's book is a solid - research effort, based on examination of court papers in some 2,500 divorces, under both the old and new laws; in addition, she has extensively interviewed lawyers, judges, and divorced men and women before and after their decrees. Until a generation ago, she reminds us, divorces were frowned upon and difficult to obtain. Our society felt strongly that it was important to keep families together. In this context, men who wanted their freedom were expected to pay a price for it. Generous alimony awards, Weitzman reminds us, had a twofold purpose: ''rewarding the woman's devotion to her family'' and ''punishing the husband for abandoning his wife.'' These attitudes crumbled as the national divorce rate soared. By some measures the rate has tripled since 1940. In that year the country had 165 divorces for every 1,000 marriages; by 1980 it was 497 per 1,000. To be sure, many of these failed marriages don't really look like social problems. About 40% occur within four years of the wedding and can be thought of as not much different from the ending of a steady date. In most cases the couple have no children, and even when they do, both partners usually remarry. In another 40% of divorces the wife is apt to be in her middle or late 30s, and in almost all of these cases there are young children. Finally, about 20% of all divorces now involve substantially longer marriages, with the wives typically in their 40s and 50s at the time of the breakup. The Divorce Revolution focuses on these last two groups and argues that in both of them divorce is generally a tragedy for the wives. In ending attribution of blame, no-fault looks on both partners as equals and proposes to split property down the middle. At least, that is what the lawmakers expected to happen. In fact, Weitzman says, equality is an illusion and the fifty-fifty split is more often than not impractical. Increasingly, the author tells us, ''divorce is a financial catastrophe for most women.'' They have several problems. In most middle-class families, the principal asset is the house. Even if the judge orders it sold, with half the proceeds going to the wife, she now finds herself in a much smaller house and, since she doubtless has custody of the children, with much less elbow room. She will probably not be awarded alimony -- only 15% of women get it nowadays -- but even if she is, and even if the checks arrive regularly, the payments tend to be small, averaging around $250 a month. Moreover, alimony awards now tend to be short term. In the name of equality, the ex-wife is receiving the alimony only during the temporary period when she's presumably preparing to go back into the labor force. THE PRESUMPTION is hard on a lot of ex-wives. In fact only a third of the women Weitzman interviewed had worked regularly before the divorce, and most had modest jobs intended to bring in extra income. Many had hardly worked at all. As one woman put it, ''There is no way I can make up for 25 years out of the labor force.'' In other ways, too, the logic of equality works against divorced wives. It requires that the ex-husband's child-support payments provide only half of what's needed to raise the kids. Making matters considerably worse for the women, default on these payments is rampant. Weitzman found that men earning $50,000 were as likely to be remiss as those making half that amount. Men behave badly toward their children in a dismaying number of cases. When it comes to custody, they tend to talk a good game. In Weitzman's interviews, over half said they wanted the children to live with them. However, only 13% made any such request in the actual petition. And a lot of fathers stop visiting altogether. One study cited by the author indicates that over half the children of divorce had had no contact at all with their fathers during the past year. Since the book's interviews took place only one year after the divorce, we never learn what became of the women Weitzman was talking to. However, other data suggest that around two-thirds of divorced women with children start working, or resume working, and one way or another become self-supporting, albeit at a lower living standard. I suspect that much of the recent pressure for ''comparable worth'' comes from working women who are divorced and feel strongly that they need something closer to a ''man's wage'' to support their families.

The group that evokes Weitzman's greatest concern is older women who have been left by their husbands. Under the old law, most of them would have been judged the injured party and would routinely have been entitled to redress. Under no-fault, they are deemed equal and told to get a job. ''My husband decided he wanted a younger woman,'' one wife of 30 years told Weitzman. ''He broke our contract . . . But I'm the one who is being punished.'' The insult is more than economic. At the time these women married, society told them homemaking was an honorable occupation and that it offered lifetime tenure. They feel betrayed, Weitzman says, because someone out there has ''changed the rules in the middle of the game.'' Meanwhile, divorced men do well economically under the new laws. Defying the logic of equality, most husbands are allowed to keep at least two-thirds of their income. Weitzman's data indicate that a recently divorced father in a bachelor flat gets a 40% or so rise in his standard of living. How come men get off so lightly? Some conceal sources of income or assets, while others contrive to delay raises or bonuses until the divorce is final. Furthermore, courts seldom view a business as having been built by joint efforts, with the wife entitled to a half share. Many of the problems Weitzman is describing would be largely solved if everyone just got married again. But the marriage market favors divorced men over divorced women. Almost any divorced man who wants to can remarry. But the most recent Census Bureau data show that half of all divorced women in their late 30s do not remarry; among those in their 40s, two-thirds never do; and among those past 50, only one in eight finds a new partner. Doubtless many of these divorced women find a single life satisfying. But Weitzman's data suggest that even those who are perfectly happy without male companionship are apt to feel bitter about the absence of a male income. A few caveats to all of the above: While The Divorce Revolution is not a feminist tract, it examines no-fault divorce largely from the standpoint of women, who are seen as its victims. Their husbands are occasionally quoted, but what they say is seldom pursued; nor does Weitzman work very hard to understand the behavior she brands as irresponsible and selfish. Furthermore, we never hear from any of the husbands' new wives or companions, who would doubtless put forward a quite different women's perspective. ONE WEAKNESS of Professor Weitzman's study is that it never clearly addresses a dilemma we now confront in our divorce laws. The author is apt to leave you thinking that the present arrangements are not only tragic for many women but socially undesirable as well. While not all marriages in the past were romantic idylls, at least they endured. Americans could assume that most children were being raised in stable homes; men were expected to stick it out as a matter of duty. If current trends continue, 60% of today's youngsters will spend some part of their childhood living with only one parent. Abundant + evidence suggests that in general two parents are better than one, and even if you dismiss the psychological dimensions of that statement you are left with the dismal economics of female-headed households, which surely implies foreshortened opportunities for a lot of young lives. It is certainly plausible that no-fault divorce, simply by making divorce easier, has contributed substantially to these problems. Does that mean that we should want a return to the old law? It is hard to believe that anybody wants to go back to the days of adultery trials and guilt assignment. Weitzman herself does not propose going back. What, then, does she want? She would like divorced men to pay somewhat more, but her prescription in this area seems muffled. To be sure, nobody else is describing a system of divorce without losers.