In Washington, you can dine with senators or ambassadors, if you are not careful. But you can also at least dream, as I do, of dining with Judith Martin. Anyone who does dine with her should be careful, but may feel free to eat cold asparagus with his fingers.

Regardless of anything you may have heard to the contrary, Judith Martin is the National Bureau of Standards. Under the name Miss Manners, she writes columns, a selection of which has been published as "Miss Manners' Guide to Excruciatingly Correct Behavior." It is rich with maxims (such as: Always use the fork farthest to the left), mastery of which will make you as swanky as Anthony Eden or Audrey Hepburn. However, if your children are, like some I know, inclined to eat even mushroom soup with their fingers, the news about asparagus should be kept from them.

But her book should not be praised for anything so vulgar as utility. Read it for the snap, crackle and pop of Miss Manners' prose which, like any distinctive style, expresses a personality. Hers is compounded of verve, wit, irony, archness and an adamancy never achieved by Pope Pius IX, whose Syllabus of Errors was, compared with Miss Manners' syllabus, halfhearted.

She insists, wrongly, that she deals with manners rather than morals. Perhaps she wants to distinguish what she does from what Ann Landers and Phil Donahue do--dispense advice about staying chaste in junior high, or winning civil rights for avocados. Actually, her book is the most formidable political book produced by an American since The Federalist Papers, and it took three Americans to produce that. Her subjects are conventions, restraints, social elbow room--in fine, correct conduct. Between anarchism and Stalinism lie civilization and Miss Mannersism.

As Plato understood, there is really only one serious political topic. It is more serious than war, or even the New Federalism. It is the upbringing of children; all else turns on that. Concerning children, Miss Manners advocates strong central government. For public occasions, "a parent must develop a way of smiling at a child, perhaps with narrowed eyes, or a way of holding the child's wrist, which conveys to the child that he is storing up serious trouble." A parent also must know how to stare at a child in a way that will cause him to utter whatever phrase is called for, such as, "I'm sorry I broke your lamp."

Miss Manners knows she is leaning into the wind--a sirocco, really--of an age in which disagreeable table manners are considered evidence of democratic sympathies and coarse speech a sign of perfect honesty. In an age absurdly sold on sincerity, Miss Manners is rehabilitating hypocrisy. Without it, people will say what they think and do as they feel--a prescription for civil war.

I am sure a becoming blush mantles the cheeks of Miss Manners when she deals with the subject uppermost in the public's mind. Letters, which it is her humanitarian calling to answer, indicate that the topic is sex:

Q. "Dear Miss Manners: What should a lady keep on hand for the comfort and convenience of a gentleman guest who may be spending the night unexpectedly? An extra toothbrush? Shaving equipment? Perhaps a comfortable bathrobe? Slippers? Should I keep them in different sizes (small, medium, and large)? I'm only interested in being a gracious hostess."

A. "Yes, Miss Manners can see that. But what are you running there? Or rather, as Miss Manners deals in manners, not morals, what do you want to appear to be running? Suppose you were overcome with passion while visiting and were then offered a wide choice of sizes and styles in nightgowns?"

Modern life does make one think, and it is nice to delegate some thinking to Miss Manners. This is an age of "liberation" from the gentling delicacies that make liberty endurable. It is an age with new vices (such as "self-gossip"--nattering on in public about one's private life) and a jarringness, exemplified by the telephone, which Miss Manners likens to a postman who compels you to read the mail the instant he delivers it.

Miss Manners' task is the daunting one of defending conventions in a nation in which the word "conventions" calls to mind only quadrennial occasions for bad political manners. Her guide for the perplexed contains 700 pages, every one pleasurable, but she--ever considerate --distills them to two guidelines, one of which will serve in any situation:

(1) Don't.

(2) Be sure not to forget to..