In the next few weeks, I became acutely aware of how often I was not addressed as Ms. socially. School officials, car mechanics and telemarketers all used Mrs. or Miss, hitching it arbitrarily to my surname or my husband's.

I began asking friends when and by whom they are called Ms. For most, it happens only at work. An administrator at my daughter's elementary school told me that although many teachers choose Ms. as a courtesy title, most students call them Mrs. whether they're married or not. And so it seems that Ms. -- popularized in the '70s and intended to elide marital status as Mr. does -- has become the norm in the professional world. But it hasn't stuck socially. Why?

Certainly, Ms. carries '70s feminist baggage that's anathema to post-feminists and anti-feminists alike: To them, it's not just the name of an eye-crossingly boring magazine, it's a title only fist-thumping proselytizers adopt.

They might be surprised to learn that modern feminists did not come up with Ms. in the first place. The title's earliest documented appearance was on the 1767 tombstone of a Massachusetts woman named Sarah Spooner. Some scholars have theorized that it was first used, like Miss and Mrs., as an abbreviation for Mistress, a 14th century translation of the French maitresse (a term of respect for women of prestige).

In the 17th century, Mrs. was used for adult women, married or not; Miss was used for girls. Only in the late 18th century did these titles begin to denote marital status, possibly as a result of the Industrial Revolution, during which women began working outside the home, and needed their sexual availability clarified.

Though Ms. has been attributed to first-wave feminism, its use and specific meaning during the late 19th century are unclear. In the 1940s, however, it was appearing in secretarial handbooks as a counterpart to Mr. Second-wave feminists embraced it, and in the debut issue of Ms. magazine in 1972, the editors explained the title: "Ms. is being adopted as a standard form of address by women who want to be recognized as individuals, rather than being identified by their relationship with a man." By the 1980s, according to public opinion polls, about a third of U.S. women endorsed its use.

In an increasingly egalitarian culture, with more women marrying later (or not marrying at all) and retaining their birth names after marriage, Ms. is more fitting than ever. It's equally useful for divorced women who shed their married names.

But for a courtesy title intended as a neutral counterpart to Mr., Ms. is larded with sticky, often contradictory associations. For example, a 1998 survey of 10,000 Midwesterners revealed that women who use Ms. were perceived as better educated and more independent, outspoken and self-confident than those who use Mrs. or Miss. But they were also presumed by the respondents to be less attractive and less likely to be effective wives and mothers.

Of course, the resistance of traditionalist folk to Ms. comes as no surprise. What stumps me is the schizoid use of the term by female professionals. How does one explain the career women who use their birth names at work and their husband's names socially? What about the divorced businesswoman who told me that her teenage son's friends call her "Miss Thompson," which she considers to be a nice conflation of Ms. and Mrs. Or the New York Times weddings page, which is filled with female lawyers and executives who "will use [their family names] professionally."

Neoconservatives, socialites and the pre-feminist generation aside, why would a 21st century woman choose to identify herself foremost as a wife? And if she does, why only away from work?

Hoping for illumination, I turned to an arbiter of social etiquette, Miss Manners (columnist Judith Martin), and found my identity crisis theory immediately confirmed. I dialed her number wondering whether to address her as "Miss Manners" or "Ms. Martin," but found that her secretary referred to her as "Mrs. Martin."

In print, Miss Manners has called Ms. "a clever, useful invention." But she wisely cautions that "in this period of transition, it is courteous to address people in the fashion with which they feel comfortable." When I asked her if this transition would conclude with the exclusive use of "Ms.," she said: "If we're lucky, 'Ms.' will eventually become the standard female title."

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