MASTERS AND Johnson on Sex and Human Loving may be the last book on sex you'll ever have to read. Everything is here.

Who gave masturbation such a "bad name"? It was Swiss physician S. Tissot (1728-1797) "who transformed masturbation from a simple sin to an illness that had to be cured."

Will developing "erotic artistry through diligence, practice, and . . . single-minded purpose" pay off with skyrockets as you move through your sexual life? Sorry, no. Sexual pleasure depends less on "mechanical proficiency" than on "how two people relate to one another."

Has youthful sexual freedom made for more stable marriage later on? Apparently not. More premarital sex may correlate with more extramarital affairs and unhappiness in marriage.

Indeed, this is not the kind of book we've come to expect from William H. Masters and Virginia E. Johnson, the clinicians of sex whose published findings (Human Sexual Inadequacy in 1970, and The Pleasure Bond in 1975) may have changed permanently how we view our sexual selves. They are the physician and psychologist -- husband and wife since 1971 -- who used science to prove that sexual behavior is learned and that we can learn the pleasures of intimate freedom.

For one thing, Masters and Johnson on Sex and Human Loving has a full-fledged co-author, Robert C. Kolodny, a long-time associate at the Masters and Johnson Institute in St. Louis and currently medical director of the Behavioral Medical Institute in New Canaan, Connecticut. More important, the book is not based principally on research by Masters and Johnson but makes heavy use of the writings of some 200 physicians, sexologists, psychiatrists, psychologists, philosophers and others as distant in time as Plato, Krafft-Ebing and Sigmund Freud, and as recent as Alfred Kinsey, Carl Rogers and Helen Kaplan. Then there is the matter of the book's origin. Perhaps 90 percent of Masters and Johnson on Sex and Human Loving is drawn from a 698-page college text, Human Sexuality, by Masters, Johnson and Kolodny, apparently originally published in 1984 and revised in 1985.

While at first suspicious of what appeared to be a recycling and repackaging job, after 100 pages of Masters and Johnson on Sex and Human Loving I saw that this is indeed another unique educational effort by Masters and Johnson -- the equivalent of a Michelin Green Guide to the sexual revolution of the late 20th century. It's an immensely informative and useful book that can be read, contemplated and applied, by nearly every adult in the land. There may be no other book like it unless it's Alex Comfort's The Joy of Sex, which seems like a frivolous cousin.

The authors begin by somewhat ploddingly stating the obvious -- that since the 1960s the United States has experienced a revolutionary change liberalizing sexual attitudes and practices. Mostly for the better, they believe, because freed from taboo and hypocrisy we can grow in intimacy and sexual satisfaction; we can assume responsibility for our own sexual lives. Forces powering sexual liberation have come from all directions -- scientific research and publication (primarily Alfred A. Kinsey's landmark Sexual Behavior in the Human Female in 1953, and Masters and Johnson's own books), the discovery of an effective oral contraceptive and the feminist movement that turned liberationist as millions of women entered the work force, and other developments such as legalization of abortion in 1973 by the U.S. Supreme Court and the 1974 official decision by the American Psychiatric Association that homosexuality was not an illness.

In the broadest sense Masters, Johnson and Kolodny are describing a phenomenon enveloping our culture. Traditional authorities -- the church, the state, family elders-have lost moral force under the pressures of education and technology, monotonous work and anonymous urban life, and our human need to at least control our own intimate lives even though we cannot control a violent world bent on self-destruction.

What Masters, Johnson and Kolodny show us in broad views of our society and in detailed case histories from their research and the findings of other sexologists is that any sexual practice consenting human beings can imagine and execute is indeed being practiced even though these innovations (innovations in mass society, that is) are illegal in most U.S. states and cities.

BETWEEN 55 and 75 per cent of all American couples engage in oral sex, and similar percentages apply to unmarrieds. Masturbation has about doubled since Kinsey's original studies -- to around 90 per cent of adult males and 80 per cent of adult females. (The authors believe masturbation "is a legitimate type of sexual activity" and tell us "there is mounting evidence that lack of masturbatory experience may lead to psychosexual problems, such as impotence or anorgasmia.") Sexual intercourse among teenagers in the United States has tripled since Kinsey's research. By age 20 nearly 70 percent of unmarried women and 80 percent of unmarried men have engaged in intercourse. (One byproduct is a teenage birthrate that is "the highest in the Western hemisphere," double Sweden's and 17 times higher than Japan's). At least 25 percent of all college students have cohabited, and today some 2 million unmarried adults are living together. Premarital intercourse among women has nearly doubled-from around 50 percent to perhaps 90 percent since Kinsey's studies, further evidence of the disappearance of a double standard in sexual behavior and confirmation that the sexual revolution must be viewed as part of the emancipation of women.

There's more of everything -- vibrators and dildos, tranvestites and transsexual surgery, triads and group marriages, bathhouses and gay bars, abortions and test tube babies (more than 1,000 since 1978), "swingers" and sado-masochists, bisexuals and homosexual marriages, erotic films and nude plays, divorce and remarriage, and above all more orgasmic women and more frequent sexual experience for all -- in the new post-Kinsey, Masters-and-Johnson-shaped world in which "millions . . . think of sex as relational or recreational rather than procreative." And there is almost no question you can ask about it, no attitude you can form toward it that doesn't find answer or comment in Masters and Johnson on Sex and Human Loving.

MASTERS, Johnson and Kolodny report on what is done sexually, not what ought to be done. We own our bodies, they tell us, and how adults alone or in consenting combinations employ their bodies sexually for release, recreation, or as expression of affection is neither right nor wrong. It's preference. But they are moralists in insisting that sex is personal and is biologically designed to bring pleasure.

Toward that end perhaps a third of their book addresses the "personal dissatisfaction with sex" -- odd phenomenon in the midst of near-total sexual freedom -- "commmonplace in our society today." The authors tell us that "half of all American marriages are troubled by some form of sexual distress ranging from disinterest and boredom to outright sexual dysfunction." Unmarried adults "can't find partners who are 'right' for them." Sex is pressured. Performance is required. Erotic pleasure is frustrated.

"Sex is a form of communication," Masters, Johnson and Kolodny tell us as they examine what goes wrong and how to make it right. But freedom of sexual expression has not freed us from barriers to communication -- fear, myth, religious or parental injunction -- or freed us from false expectations of "super colossal sexual ecstasy" created by films and books that depict sex in ways that "cannot possibly be matched by our real-life sexual experiences in sustained relationships." Sex partners are not mind readers. They must tell one another what they like. To get what they want they must ask for it -- yet the majority of sex partners in the United States cannot or will not talk meaningfully about their mutual sex life.

Sex is not only a pelvic event, Masters, Johnson and Kolodny say. It is an event involving the whole person, and they and others have proved it with all sorts of physiological and psychological experiments. Our bodies blush. Temperatures rise. Biochemistry and brain waves accelerate. Fantasy races. We cannot be successful sex partners unless we are successful partners in other ways. What happens in the bedroom reflects what happened at dinner. "Always remember that good sex begins while your clothes are still on," the authors tell us. There are significant differences between the sexual needs and responses of men and women. Women tend to be multiorgasmic; men are not. Women want prolonged touching, caressing, stroking before coitus; men are more quickly aroused and spent. During arousal women's bodies show two to three times more "sex flush" coloring than men's. Men are fertile into old age; women are not.

But there are more similarities than differences between the sexes, and many of the perceived differences are social stereotypes. Men and women enjoy sex equally and at about the same ages. Men are not more promiscuous than women. Both about equally engage in voyeurism, use fantasy, want variety, struggle with boredom, and like oral sex. Both need empathy, romance, tenderness, self-disclosure, and opportunity to switch from passive to aggressive roles in sex. Both become sexually impaired when self-esteem is under attack or lost, or when driven into "spectatoring" by anxiety about performance. (Masters, Johnson and Kolodny, by the way, offer many pages of advice, procedures, and techniques drawn from their clinical experience for enhancing pleasure and overcoming impairment.)

Nearly everything they tell us about bonded heterosexuals applies to bonded homosexual men and Lesbian women, according to their research. Homosexual couples are about as happy as heterosexual couples, even though individual homosexuals have many more partners and are less successful at bonding. Regardless of sexual preference, the commitment made between couples that celebrates itself in sexual pleasure is more in the head than in the gonads. We love sexually with all of our emotional being.

If Masters, Johnson, and Kolodny had asked for advice on editing their college book for a general audience, one might have told them to cut the number of scientific caveats and qualifications. Further, to avoid such throwaways as "learning about sex is an invaluable preparation for living" and "we will not use slang terms about sex because they convey a negative message to some people." And to stop absolutely saying things like "now we shift our attention from . . . " and "we cannot conclude this section without . . . " Sometimes they write as if chopping wood.

But we want what they know, not their syntax. In reporting on "the sexual revolution of the 1960s and 1970s," they give us something akin to a unified field theory of human sexuality. They join psychoanalysis (Freud loses much), modern medicine and physiology, and at least three kinds of psychotherapy -- Gestalt, transactional analysis, and behaviorism -- to show us that sexual behavior is the physical expression of the complete personality, sexual gratification the summary of a total relationship.

This is the kind of book that could change your life.