Now and then a book comes along that should never have been written - not because it's particularly bad, but because it wastes a first-rate title on second-rate text.
The recently-published ''In Defense of Marriage'' (New York: Walker & Co.) is such a book. The world desperately needs a lucid, comprehensive, and potent statement of the arguments in favor of marriage. What author Art Carey provides instead is an explanation of why he chose, after divorce, to remarry.
Perhaps that's too harsh a judgment: There's a lot here that's worthwhile. As a writer for the Philadelphia Magazine - which in 1983 published the article from which this book grew - Carey draws together some wonderful comments by anonymous individuals on the state of their own and others' marriages. He interweaves census data, opinion-poll statistics, and observations from psychologists, marriage counselors, sociologists, and others. He provides a tart condemnation, partly autobiographical, of the false pleasures of the ''swinging singles scene.'' He identifies such major attributes of marriage as ''giving'' and ''commitment.''
Yet the book remains unfulfilled - in ways that shed useful light on the challenges facing the defenders of marriage. Among the difficulties are these:
* The salesman-slick tone of the book, while ensuring an interesting read, in the end undercuts its purpose. Marriage, after all, is far more than an Ivy-League institution: It finds some of its staunchest exponents among the least-educated and least-verbal members of society. That by no means implies that a closely-reasoned defense of marriage is worthless. In the end, however, marriage is not defended merely by shifting the intelligence into verbal overdrive and overwhelming the issue with self-analysis.
* More damaging than tone is lack of substance. At bottom, this book says very little about marriage as an institution, legally sanctioned by society and designed to ensure the welfare of the race. The book is mainly a defense of nonpromiscuous cohabitation - with the issue of wedlock left undiscussed. In an age of promiscuity, of course, every assertion of faithfulness and commitment is welcome - and Mr. Carey is quite vehement in defending those values. But one searches in vain for arguments in favor of marriage in preference to merely living together - or, for that matter, for reasons to prefer heterosexual relationships to the kind of homosexual liaisons which (say their proponents) also depend on faithfulness and commitment.
* But the most astonishing void is the lack of discussion of children and family. They simply don't figure into Mr. Carey's tour d'horizon. Figuring prominently, even pruriently, however, is sex. Despite the author's righteous denials, it emerges as the centerpiece of marriage. But procreation? It hardly gets a nod. Nor is there any hint of the careful thought many couples take in deciding not to have children. Marriage, in Mr. Carey's view, appears to have little purpose beyond the personal satisfactions of the wedded pair.
Each of these failures, moreover, points up an underlying problem facing modern marriage. The problem is one of counterfeits. What most challenges marriage is not out-and-out misanthropy or misogyny. It is the imitation of marriage that looks just enough like the real thing to be misleading - the self-entwined introversion that ignores children, the look-alike arrangement that ignores legal sanctions, the intensely self-conscious relationship that ignores quiet simplicity.
In the end, then, this book is itself a counterfeit. The real defense of marriage must focus on the common man and woman, come to terms with the institutional framework of matrimony, and address the place of children and family. For marriage involves more than two people standing face to face, wholly absorbed in one another. It involves a couple standing side by side, looking out together into a broader world.