THE LITERATURE OF SEX is a vast and gloomy one, consisting in large part of gratification denied; the reader keeps waiting for the author to get to the good part, and the author almost never does. It is a wonder that we persist and yet -- moths to the flame -- we keep plugging away, returning again and again to yet another pseudo-Viennese revelation that the Methodist preachers were right all along (it really does drive you crazy) or flipping furtively through yet another novel, only to discover the writer employing the language of Bulwer-Lytton to describe something that closely resembles the disassembly of a carburetor.

Writers on sex labor under the same handicap as writers on sports. That is to say, they find themselves reporting an event that everybody agrees is awfully important, but which in practice turns out to be pretty much the same old event under slightly different skies. There are a remarkably limited number of ways to steal second base, and while the number of ways one can steal another's spouse are infinite in their variety, the number of variations on subsequent events do not become spacious until the happy couple gets out of bed.

Masters and Johnson aren't much help and neither is the engaging Dr. Alex Comfort -- we knew all that already, for heaven's sake; it's how we feel about it that counts -- while the principal discovery of the late Dr. Kinsey was simply that an enormous number of adult American citizens were willing to kiss (or something) and tell. I suppose all this may look very different from the perspective of Anita Bryant, but somehow I doubt it. There may or may not be such a thing as too much sex, but unless you happen to be drunk, crazy, desperate, or 14 years old, there is definitely such a thing as reading too much about it. The dangers of jaw dislocation and hyperventilation from the potent yawns that ensue cannot be stressed too strongly.

I now realize that the antidote for this sorry state of affairs consists of a levelheaded Scotswoman, but like great advances, the fact didn't become obvious until Reay Tannahill -- the levelheaded Scotswoman in question -- published Sex in Historn, which she has just done. Those who pay attention to such things will remember her as the author of the similiarly titled Food in History, a charming, discursive and impressionistic study of man's other abiding passion. The inevitable sequel, Sex in History is equally charming but, wisely, more businesslike. Although the English language has evolved a rich and fluent vocabulary when it comes to beans and strawberries, it is lugubriously poverty-stricken on the subject of carnal knowledge, largely because the English-speaking peoples have gone completely overboard on the idea of the Zone of Shame -- the area, as defined by 19th-century evangelist Dwight Moody, between the human neck and the human ankle. Still, as Thoreau said of the trout in the milk, when something becomes that overwhelmingly if negatively important to us, it ought to suggest something, and it is this something that Tannahill attacks with tremendous verve.

No such survey would be complete if it failed to inspire a quibble or two (for example, Central and Eastern Europe borrowed the double eagle from the Byzantines, not the Turks) but on the whole, Tannahill renders yeoman service to her subject. I have no way of knowing if the long subjection of women dates from the neolithic revolution, when the menfolk, keeping watch over their herds and flocks, made a sensational discovery about procreation, but it sounds right. More easily demonstrable is Tannahill's contention that civilized Western man has proved remarkably uninterested in the practice of sex but positively obsessed with its regulation, a trend that peaked when the early Christian fathers proclaimed almost everything illegal, including some things that had never before been illegal anywhere in the known universe. Here the Chinese, the Japanese and the inhabitants of the Indian subcontinent have the better of us, with their frank admission that copulation is not only fun but good for you, especially if you happen to be a man; it charges up the old batteries.

Elsewhere in these pages, one discovers that Egyptian women would have been better advised to use elephant rather than crocodile dung as a contraceptive aid (elephant dung is slightly acid), that Aristotle was dead right about olive oil, that Greek homosexuality was something of an Athenian fad, and that the population of Rome was artificially depressed by a combination of alcoholism and lead poisoning. Courtly love originated in Islam and, strangely mutated, began the long, slow process of turning women from chattels into human beings.

The Mongols had a reputation, perhaps undeserved, for zoophilia. Early Christian hermits had housekeepers. The deification of respectable womanhood in Victorian times caused both a great prostitution boom in England and a precipiate fall in the American birth rate. Latter-day feminism may be a proximate cause of the pornography explosion. Female boredom, an occupational hazard in Turkish harems, was also a contributory factor in the fall of Rome. There are many different ways of making a eunuch. Brigham Young had 27 wives. And almost everything is still against the law somewhere, except in Japan.

What fun. Most of the above propositions, and many more, are arguable, of course. And because the book is aptly, cleverly and lavishly illustrated, an agrument is precisely what you're likely to get if you're incautious enough to try reading it on public transportation. It is a risk well worth taking. Sanity on the subject of sex is all too rare; wit is in even shorter supply, and an engaging style is about as commonplace as eyebrows on an egg. Three cheers and a tiger, therefore, for Reay Tannahill.