But Firestone's vision is not only a reaction to anti-feminist dystopias. It's also, as I said, part of a separate feminist tradition. Here, for example, is Ursula K. Le Guin from The Left Hand of Darkness, describing a society of hermaphrodites in which, to paraphrase Firestone's words, not only male privilege, but the sex distinction itself is eliminated:

Consider: Anyone can turn his hand to anything. This sounds very simple, but its psychological effects are incalculable. The fact that everyone between seventeen and thirty-five or so is liable to be..."tied down to childbearing," implies that no one is quite so thoroughly "tied down" here as women, elsewhere, are likely to be—psychologically or physically. Burden and privilege are shared out pretty equally; everybody has the same risk to run or choice to make. Therefore nobody here is quite so free as a free male anywhere else.

And here's Joanna Russ in The Female Man imagining an interview between earth men and a woman from a future all-female society:

MC: ...Don't you want men to return to Whileaway, Miss Evason? JE: Why? ME: One sex is half a species, Miss Evason. I am quoting (and he cited a famous anthropologist). Do you want to banish sex from Whileaway? JE (with massive dignity and complete naturalness): Huh? MC: I said: Do you want to banish sex from Whilewaway? Sex, family, love erotic attraction—call it what you like—we all know that your peope are competent and intelligent individuals, but do you think that's enough? Surely you have the intellectual knowledge of biology in other species to know what I'm talking about. JE: I'm married. I have two children. What the devil do you mean?

Le Guin's novel was published in 1969, the year before Dialectic of Sex; Firestone probably hadn't read it when she wrote her own book. Russ' novel The Female Man, was written in 1971, and it seems quite possible that she had read Firestone's work.

But I don't think it matters that much who did or did not influence whom. What does matter is that Firestone wasn't some kind of mad visionary. Or if she was a mad visionary, she wasn't the only one. Susan Faludi quotes Kate Millett as saying, "I was taking on the obvious male chauvinists. Shulie was taking on the whole ball of wax. What she was doing was much more dangerous." Which may well be true—but there were clearly other writers at the time (and earlier) who were also trying to take on the whole ball of wax, and reimagine society from reproduction and family on up.

Giving Firestone a context makes her, in some ways, less radical, or at least less unique. But I think it also can make her more relevant. Her dreams weren't just her own dreams. Her brilliant blending of Marx and feminism, in which she sees women's labor as the prototype of all labor—that becomes not just a singular insight, but part of a conversation in which writers like Le Guin and Russ and Gillman and Marston were actively trying to figure out how biological difference is linked to oppression, and what changing that would mean. Her Freudian insistence that straight sex is not normal sex, and her argument for "polymorphous perversity" was part of the long, fruitful conversation between feminism and queer thinkers. Firestone's feminist utopia was also a queer utopia, and has only gained in relevance as queer politics and feminist politics have become more intertwined.

It's true that Firestone was a visionary; it's true that, for all her analysis of the past and present, much of her energy was focused on the future. But I don't think that cuts her off from her own time, or from ours. Looking forward is, on the contrary, one of the main ways we interact with the present. In life, after writing her book, Firestone lost connection with her movement and her peers. Seeing her in the context of feminist science-fiction is one way to give her back her sisters.