"I was always more interested in boys than other girls were," Nancy Friday cheerfully admits. "When I was growing up, men occupied my dreams night and day." Thus, having explored women's sexual fantasies in My Secret Garden and Forbidden Flowers and then her relationship with her mother in My Mother/My Self, it was probably inevitable that Friday would next examine Men in Love, her new book subtitled Men's Sexual Fantasies: The Triumph of Love over Rage (Delacorte Press, $12.95). As Friday says, "The more I learned about women's sexual identity, the more I kept wondering, 'But what's it like for men?' "

Her answer in Men in Love, already at the top of the best-seller list, is based on more than 3,000 responses to an appeal she had printed on the last pages of Flowers and Garden. In it she urged men to send her their sexual fantasies ("anonymity guaranteed"). To augment her findings, she says, she also served as a sex fantasy columnist for a men's magazine.

Born in Charleston, S.C., and a graduate of Wellesley ('55), Nancy Friday, who is in her mid-40s, commutes between a home in Key West, Fla., and a West Side Manhattan apartment. She shares both with her husband of 16 years, Bill Manville, author of Good-bye and Saloon Society. Recently she talked with Barbara Rowes of PEOPLE:

Why do men fantasize?

Somebody once said that the most powerful sexual organ is between our ears, not our legs. Sexual fantasies are maps of desire, mastery, escape and obscuration; they are the navigational paths we invent to steer ourselves between the reefs and shoals of anxiety, guilt and inhibition. They are conjured up when men want to be sexually aroused. Everybody fantasizes, if he or she is sexually alive.

Where do these fantasies come from?

A child is a sexual creature. When a young boy is discovering his own sexuality, the strong attraction of it and the need for parental love often clash. Early on, the dramatic conflict between sexuality and security is often resolved in fantasies. Generally, as boys mature, parents no longer figure in this conflict, but the fantasies are basically the same.

Then are all sexual fantasies rooted in childhood?

No. There are adult needs and desires expressed as well. I happen to believe that monogamy for many men is almost unnatural. So what can men do who decide to remain faithful within their marriage but are attracted to other women? Many times they satisfy themselves through fantasies. They do things in fantasy that might prove very frightening in real life, for instance explore the neighbor's attractive wife or a secretary in the office, maybe even engage in group sex.

What is the difference between our dreams and sexual fantasies?

Dreams are the expression of the unconscious while we are asleep. Sexual fantasies are ideas, images, pictures in our mind while we are awake. They're a combination of the unconscious and conscious. If people could begin to look at their sexual fantasies as easily as they accept their night dreams, we'd all be a lot healthier about our sexual identities.

In a swinging society where anything goes, does fantasizing tend to diminish?

Absolutely not. Fantasy isn't something you run out of. The more sexually active you are, the more sexual fantasies you can have. Even rock stars, who have everything available to them, don't run out of fantasies. But I don't know how good it is to live out all your fantasies.

Do men really want to act out their fantasies?

On the contrary. The majority of fantasies are not suppressed wishes. In their letters men say very strongly that while in fantasy they are swingers, in reality they would be too frightened to, for instance, have sex simultaneously with their wives and another man. It would set up too much ambivalence and anxiety, but in fantasy it's fun.

Who fantasizes more, men or women?

Ten years ago I would have said women, because their sexual reality was more limited. Generally men had more experience, more mobility. But as opportunities for sexual activity have increased, I'd say the two sexes have become about equal in fantasizing.

What is the biggest turn-on for men?

The major theme in men's sexual fantasies is the sexually aroused woman. It's still hard for most men to believe that women enjoy sex, that they have the same sexual appetites that men do, that they might really enjoy a one-night stand.

Why is this difficult for men to accept?

Most men grow up thinking women are sexually different from them, that women believe sex isn't nice. Their mothers start by pushing their hands away from their genitals. Then later in life women push them away altogether. Women set conditions for sex. This doesn't make sense to a man. He doesn't understand sex as a conditional thing. How many men do you know who will only sleep with a woman if she promises to love him forever and call him tomorrow? The idea that there is a woman out there who enjoys sex unconditionally is hard for a man to accept—but is a wonderful fantasy. For once in his life he is not being put in the role of the animal.

In reality, how does the average male react to the lustful female?

Some men would like to meet her, but they are in the minority. The fantasy woman runs head-on into the man's image of himself as the aggressive one. How does the stereotypical man in this culture make it with an equal while also being macho? How is he going to initiate sex and come on like a stud if she is as excited as he is? The two concepts don't mesh.

Do men's and women's fantasies differ?

One fantasy which separates men and women is the idea of sex with more than one person. It's a commonplace in fantasy and reality that men would love to go to bed with two women. But women get very nervous about sex with more than one person. They feel threatened. They are raised with the idea of one-to-one relationships. Men are more generous, both with love and with sex.

Are you saying most men wouldn't mind their wives having sex with another man?

No, most men do not want to share their wives in reality, but in fantasy it's possible. For most women, it isn't possible, even in fantasy.

What about open marriage?

Nine and a half times out of 10 it is the man who encourages the woman to go into it. I haven't seen many open marriages that have worked. I think biologically we are attracted to more than one person, but given society and our needs, monogamy works better.

Who are the women in men's fantasies?

The woman always has an identity. She is not a faceless stranger. She's the woman next door, his wife's best friend, an old girlfriend. This goes against the popular thinking that a man wants to make love to anything in a skirt.

What about incest?

Men were not afraid of such fantasies. In fact, some claimed to have had actual relations with their mothers. But no one reported sex with their daughters, not even in fantasy.

What was men's greatest fear?

Most men feared homosexual tendencies. By contrast, the most heterosexual and conservative women would admit to having fantasies about other women. They felt no guilt or threat to their gender identity by confessing this. But straight men cannot say it in our culture. Revealing that they have a fantasy about another man is too threatening to their masculinity.

What surprised you most?

Psychoanalysts often used to express the belief that most men's fantasies deal with sadism. This isn't what I found at all. The men I heard from were not into hurting women. They did not get aroused that way.

Aren't the men who confessed their fantasies to you, often signing their names and addresses, basically exhibitionists? How can you trust what they wrote? Isn't your sample a very atypical one?

I don't know what "typical" means in human relations. Nor do I believe any report on human sexuality can be totally unbiased. Mine isn't a scientific report. I'm not competing with Kinsey. But I have clearly stated my sources. And after consulting with numerous psychologists, I believe mine is representative.

What is the benefit in recognizing sexual fantasies?

After I wrote My Secret Garden, I began getting letters from women expressing gratitude. "Thank God you wrote that book," they said. "I thought I was the only one." Your sexual fantasies are one of the most valuable X-rays you'll ever have. They provide a look at your sexual psyche. They can tell you so much about yourself.

What can women learn from men's fantasies?

If women really want equality, we have to wipe the slate clean. It no longer matters in the largest sense what men did to us for the last 200 or 300 years. Now we have to try to understand what it's like for men, how they feel about the changing roles in this society, what it means to be a man in this culture. It's time to liberate men by understanding them and working with them. The decade of the '80s is the age of men's liberation. Women have to start by lending a helping hand.