(FORTUNE Magazine) – HAVE YOU ever wondered whether you should invite the boss home for dinner, or what to say when you're late to an important business meeting? If you have, you may need help from Miss Manners. This high priestess of punctilio, whose real name is Judith Martin, gives such sound and sane advice on how to navigate the treacherous social shoals of modern life that she has been dubbed the National Bureau of Standards. Though she majored in English, Miss Manners concedes that her true academic pursuit at Wellesley College was gracious living. As a Washington Post journalist for 25 years, she covered social life at the White House and on embassy row. Her syndicated advice column appears in 250 newspapers in the U.S. and abroad, and she has written two best-selling ) books on etiquette. A third, called Miss Manners' Guide for the Turn-of-the- Millennium, due out later this fall, takes up the social do's and don'ts of the workplace. During a recent rendezvous at a suitable Washington restaurant, Miss Manners discussed business etiquette with Fortune's Brian Dumaine. In the process she was kind enough to overlook any faux pas he may have committed.

It's an important meeting -- the big boss, clients are there -- and you arrive 15 minutes late. What do you say? Of course you apologize. Business hours are much more strict than social hours. Now, if you can say, ''I'm sorry, I was just closing the 'blank' deal,'' you get both the apology and the excuse in. But don't apologize to the point of groveling because that takes too much time.

Do you make up an excuse like the train was late? That is really stupid. Most of the time an excuse doesn't need bolstering, and the more bolstering it gets, the more suspicious people become. If you say, ''I'm sorry, the planes were down,'' and I say, ''That's funny, my niece called from the airport, and she just flew in,'' then you're in trouble.

You're in the same meeting, and your boss says something factually wrong. Do you correct him? You do not contradict your boss in public. Now if the information is trivial, you let it pass. If it's essential, you find a tactful way of bringing the material in without contradicting him. You say, ''We had a report in this morning that said that . . .'' or ''We may have misled you on that'' or something of that nature.

Should you feel obligated to raise a question or make a comment in a meeting even if you don't have anything particular to contribute? I don't see that you should waste people's time if you have nothing to say. If you don't have anything worthwhile to contribute, shut up.

If someone lays claim to your work in a meeting, should you speak up? Yes, I think you should. I don't think that business matters require you to be self-effacing. Part of the purpose of manners in the professional world is to provide courteous ways to make controversial, contradictory, or hostile statements. If you attack people directly, they must defend themselves, and you go off from the subject. You don't say, ''You bastard, you're lying,'' because then he says, ''I am not,'' and you have a melee. All right, so someone takes credit for your work. Then you kindly say, ''Perhaps you have forgotten that I documented that point in my report of June 1, which you might want to look at to refresh your memory.''

What should you do when someone walks into your office to chat and you suddenly realize he's reading a memo that's lying on your desk or he's glancing at the computer screen in back of you? You take the papers off your desk and you shuffle them and you put them in a drawer, or you turn off your computer screen. That makes it very clear that he knows that you know. Now if you think the person has purloined some information, you might say, ''Of course, you understand that anything you may have accidently seen in this office is not available to you.''

Is it ever proper to comment on a female co-worker's looks? If we are friends and you meet me at a party and you say, ''Don't you look lovely, what a lovely dress,'' that's one thing. If I am trying to make a business presentation and you say, ''Gee, you look adorable,'' I wouldn't like that because it's a way of saying, ''I recognize you first and foremost as that lovely social creature, a lady,'' which means I'm not really tuned into your primary role here as a serious worker.

Where do you draw the line on what constitutes sexual harassment? Well, sexual harassment is illegal and properly so. There are many manifestations, and, obviously, there is a gray area between what some people would call social chitchat and pleasantries and other people would call sexual harassment. If I were a male, I would err on the side of caution. If you say to a secretary, ''My, aren't you a pretty little thing,'' it is a way of saying I'm noticing you as a woman, which is jarring and slightly threatening to the woman who is there in her role as a worker. It cuts to the personal in an unpleasant way.

What do you say to the office Casanova who's making plays for just about every woman on staff? If I were his boss, I would say, ''Keep it out of the office.'' The boss should not preside over people's personal lives, but he has a right to demand that one's personal life not intrude into the office.

So you're generally not in favor of office romances? I'm in favor of having them conducted in people's private time. If you want to give someone meaningful stares, and they're staring back in a meaningful way, and it doesn't disrupt the office, and you're having a hot romance after hours, I wish you much happiness.

Should you invite your colleagues to a wedding? I'm firmly against it unless they happen to be friends. It's a personal event. It's a burden on people who really don't care about you personally. I may like you perfectly well as a co-worker, but I have never thought enough about you to have any interest in whether you're happily in love or not.

Is it ever proper to bring your kids to the office? It's a complex problem. With the old system, where mama was home taking care of the children, you brought them in once a year to show them what daddy does, and that is a useful and not very disruptive thing to do. The problem now is that mom is not at home, and you do not have any solution to the horrendous problem of child care that parents face. I have a lot of sympathy for the incredible emergency when all systems have failed and there's no one to look after the child, so I certainly don't want to make a blanket condemnation of this. But basically, no, children do not belong in the office. It's unfair to the children, it's unfair to co-workers, it's unfair even to the parent. You can't work and attend to a child at the same time.

How do you turn down a client or supplier who offers you some sort of gift, whether it's money or a small present? You say, ''Thank you very much. I'm so sorry, but I'm unable to accept it.'' By the way, giving Christmas or birthday presents within the office is highly inappropriate. If you wish to reward your employees, give them bonuses at the end of the year. Money is the proper exchange in the business world, and presents are the proper exchange in the social world.

If you're playing tennis with the boss, do you let him win? No. Etiquette does not require you to falsify your achievements in any respect in order to ingratiate yourself with people. If you want to do that, if you think that will help your career, I personally would find that an unappealing attitude.

But do you think it might actually help one's career? I have no idea and prefer not to think about it.

Should you invite your boss to dinner? Absolutely not. That's the most classic, comic stress situation, like Dagwood and Blondie inviting the boss, Mr. Dithers, home to dinner. The roast is burned, and there goes your career. And suppose you live in a style that your boss might not like? Well, it really is a stupid idea, isn't it? You - should instead put your energy into impressing him with what a good job you can do.

Any caveats when traveling on business with members of the opposite sex? It always was assumed that opportunity provided material for scandal. The assumption was that a man and a woman traveling together had the opportunity to do something, shall we say delicately, in the personal realm. I'm abolishing the idea. Today, if a man and a woman are traveling together on a business trip and are seen having breakfast or dinner together, you would have to know something more damaging about them to start giggling that, aha, they must be involved. How dare anyone presume that.

Should you offer to carry a female colleague's suitcase at the airport? If the colleague has just recovered from a heart attack or is overburdened, of course you would help, male or female. But if the only reason you're doing it is because she's a lady, no.

So you can have good manners without being the office wimp? One of the major mistakes people make is that they think manners are only the expression of happy ideas. There's a whole range of behavior that can be expressed in a mannerly way. That's what civilization is all about -- doing it in a mannerly and not an antagonistic way. One of the places we went wrong was the naturalistic, Rousseauean movement of the Sixties in which people said, ''Why can't you just say what's on your mind?'' In civilization there have to be some restraints. If we followed every impulse, we'd be killing one another.

You really think about all this quite a lot. It's my life work. I would hope so.