TO THE STEADILY growing list of those who have taken it upon themselves to advise this most unmannerly age on matters of manners must now be added the name of Quentin Crisp. The author of The Naked Civil Servant, How to Become a Virgin and other weighty tomes is a flamboyant fellow who has carried the androgynous style to new heights -- or, depending on one's point of view, new depths -- but when it comes to questions of behavior he settles on the side of discretion, courtesy and civility. Crisp himself may be a round peg whom the world's square hole cannot accomodate, but he has learned his lesson and he recommends it to us as Crisp's First Law: "If you feel that you cannot comply with the morality of the world you must do everything else you can to be agreeable."

Like almost everything else in Manners from Heaven, this is wiser counsel than at first it may seem. Crisp is a most amusing writer who cannot resist the bon mot, but beneath the seeming facility and cynicism of his prose there is a considerable body of knowledge about the compromises that are necessarily made if people are somehow to manage to exist in groups. Unlike Amy Vanderbilt or Miss Manners, Crisp makes little effort to advise his readers about the specifics of manners; he is concerned, rather, with formulating a broader philosophy on the basis of which "manners can be employed to cope with, or outwit, the affronts of racism, sexism, hooliganism -- and the terrible things which people do to one another in the name of love."

Crisp is at pains, in fact, to emphasize that his book is in no way a guide to etiquette, which he regards as a British "class system based on snobbery and exclusion," a system of rigid rules "designed to ake people (particularly those not of one's 'class') feel ill at ease and out of place." Though he is British himself, Crisp prefers to replace formal etiquette with less formal manners, what he characterizes as the American "technique of inclusion, a way of ensuring that in our company no one will ever be made to feel he is an outcast by reason of his birth, education or occupation."

Some readers are likely to regard this as an excessively optimistic interpretation of American behavior, but there can be little question about the preferability of inclusive politeness to exclusive formality. Yet to prefer the casual to the rigid is by no means to abandon standards; the challenge is to "chart a course between the fuddy-duddy strictures of yesterday and the hapless chaos of today." Crisp writes: "A rebellion against 'too much starch' in social behavior is understandable, but a rebellion against being considerate to others is not: such a policy will surely return to haunt one -- for if you are free to be inconsiderate to others, they will certainly feel free to be inconsiderate in return, and the quality of life declines steadily. I encourage people to become conscious of their words as a means of pollution control in social relations."

Thus it is that Crisp, in his wisdom, loathes above almost everything else the propensity of the age for what he calls "a nursery-school of thought which advocates that people should be sincere: that they should be constantly expressing what's on their minds." As a considerably wiser student of human nature than those fraudulent pop-psychologists who since the unlamented '60s have encouraged us to make free with our feelings, Crisp knows that "the lie is the basic building block of good manners" and that "most people would rather be treated courteously than be told the truth." Although he does not go so far as to make it a law, Crisp does offer this eminently sane suggestion: "If a lifetime of observation of all-too-human squabbles means anything. . ., my advice is: never have a frank discussion with anyone about anything."

THIS MAY be for comic effect, but it is only a slight exaggeration of the facts of social life. Reticence is easier to live with than candor, just as Bach is easier to live with than Blondie. We live in an age of metallurgical noise that passes for music, and of social conventions that mirror it:

"In some degree a great many people have responded . . . to the influence of the young (beginning in the 1960s) and loosened their stays, unbuttoned their libidos, unzipped their psyches, and little by little, more and more, let informality reign in all areas of life. . . . With some people it became mandatory to advertise every detail of their sexual behavior constantly. To the young, forcing others to watch or listen -- be they friends, family members or complete strangers -- is the next best thing to being on television. In recent years this trend towards dispensing with formalities has become stronger and is today the main threat to our achieving a more polite society in the future. What is at stake here is not mere decorum but efficiency in a wide range of social relations. A society in which 'anything goes' is one in which nothing goes well."

Certainly that is true of sex, in a time when "lasciviousness is ubiquitously advertised: we have dehumanized sex, and then sexualized everything else -- from airline travel to soft drinks." As with virtually the entire landscape of contemporary life, we have managed to make less of more: "Instant sex is a time-and labor-saving device but, as leisure and energy are what we now have to excess, this is no recommendation. For flavor, it will never supersede the stuff you had to peel and cook. This is one of the unpleasant truths that the permissive society has brought to light." Another unpleasant truth is that permissiveness is self-indulgence, and self-indulgence inevitably produces bad manners, inasmuch as "low forms of life and the immature live in a constant state of self-centered turmoil."

Such turmoil is perhaps the most lasting legacy of the '60s, and we are far from finished with the struggle to rid ourselves of it. Quentin Crisp is not likely to be as effective a general in that war as Miss Manners has been, as he does not have the forum of a syndicated column and his book has little value as a reference work; but his counsel certainly deserves thoughtful consideration. For that, in fact, is precisely the word at the heart of his book: consideration. If we consider others, he tells us, we improve the world for ourselves. Isn't that reason enough to do so?