Etiquette arbiters used not to be asked for the proper forms that a lady or gentleman should use to address a former lover.

The problem did not exist.

Miss Manners is not so silly as to suppose the situation did not exist. If young people read as many old novels and private histories as she does, they would not be quite so smug and pleased with themselves for being the first generation in the history of humanity to have discovered recreational romance.

What is different is that people used not to go public with their liaisons.

The etiquette problem of encountering former lovers socially did not exist, because everyone was so busy ostentatiously pretending that nothing had happened that anyone who hadn't already known immediately suspected. Yet even scandalmongers in the joy of first discovery were expected to confine their reactions to a raised eyebrow and a whisper.

This is called civilization. The art of knowing interesting things without either dramatizing them for others or letting on that one knew them was a useful one that ought to be revived.

But that's enough nostalgic fussing around. Miss Manners supposes that since the question does now exist, she must tackle it.

The basic rule for polite behavior between two people who once loved each other but no longer do is that they not trouble onlookers with their unpleasant feelings or low opinions of the formerly beloved or that person's newly beloved.

Because of the prevalence of divorce, this rule is well-known, even if hardly ever observed. Miss Manners is forever having to tell divorced people that family weddings, graduations and funerals are not useful occasions for recapping their disappointments. And their own children keep suggesting that meetings for the purpose of delivering them from the custody of one to the other are not enhanced by this activity either.

In the case of lovers who were never married, such ceremonial encounters are usually not necessary. If the two are still connected through professional ties, they should be using distant business manners, anyway -- just as they should have been under business circumstances during the height of the romance.

But former lovers have mutual friends, and the accidental social encounter is not uncommon. At such times, these people need all the manners they can muster.

Mind you, Miss Manners is not assuming that their residual feelings are necessarily antagonistic. She sees various possible degrees -- warm, cold, tepid, mixed. But whatever their temperatures, former lovers are in even greater etiquette peril than that of properly -- so to speak -- divorced couples.

In addition to mutual antagonists, who are of course enjoined from expressing their ill will, there may be lovers who parted with good will on both sides and wish each other only the best, and perhaps some who might be susceptible to a reconciliation. There may also be couples in which one person is bitter and the other fond -- the latter being, paradoxically, the one who engineered the split, and the former the one who resisted it.

The danger arises from the unknown. What, if anything, did the other person say about the former love affair and how it ended? During a chance encounter, there is probably no way of knowing.

Yet the former couple has an obligation of mutual discretion. Each is entitled to his or her own version of what happened, provided this stops well short of slander. As a love affair is not, like a marriage, a matter of public record, this could include not acknowledging that a love affair even took place.

Thus, former lovers have to watch the public expression of kindly, as well as hostile, feelings toward each other. Any possessive gestures or sly references are improper. The proper demeanor of former lovers is that of friendly acquaintances -- exactly because this is simultaneously interpreted by those in the know as mere proper demeanor, and by those not in the know as mere friendly acquaintanceship.

A former lover who wishes to display something more must seek privacy. Miss Manners will refrain from pointing out that such people are well aware of how to find it.

Q: Parent and child are shopping. Child wants expensive toy, which accompanying parent does not wish to buy for him.

Casual acquaintance, a nice lady who simply adores children, sees the predicament and decides to settle the issue. She says: "Oh, c'mon, buy it for him. He's your child. He won't be a child forever."

In this situation, what is more proper for the parent to do?

1. Deliver swift kick to the shins of the nice lady.

2. Tell her child: "Darling, did you hear that? This nice lady is going to buy it for you."

What if it is candy, or something else that he is not supposed to have?

A: It is because she admires your refusal to allow your child to bludgeon you into buying things that Miss Manners is forced to point out that conning someone else into doing so, even as punishment for intrusiveness, is not the lesson you want to teach. Shin-kicking probably isn't, either.

You may be sure, however, that Miss Manners supports you in rejecting attempts to undermine your authority. Whether it is a matter of presents or candy is irrelevant -- the point is that the decisions are yours to make.

What you might say is: "You're exactly right. He is my child, and I have the responsibility of teaching him to grow up to be a considerate adult." That a considerate adult does not interfere with child-rearing is left unsaid.