Tisdale (Stepping Westward, 1991, etc.) leads an enthusiastic amateur's tour through sex in America (with a few brief forays abroad). In an inviting expansion of her controversial 1992 Harper's magazine essay of the same title, Tisdale offers a trek through sexual inhibitions, expressions, assumptions, and questions (for instance, if everyone thinks about sex so much, why do so few feel comfortable discussing it?), arriving at an increasingly fashionable pro-sex feminism. Americans are so conflicted about sex, she says, because they're caught endlessly between obsession and avoidance. Tisdale, fighting avoidance, confronts the subject head on. She checks out sex clubs, sex toy stores, pornography shops, and erotic novels, citing everyone from Roland Barthes to Susie Bright. Ancient Greece, the story of Adam and Eve, Freud, Jesse Helms, and Basic Instinct convince her that we're a nation of guilty prudes, arrested adolescents who can't sate our lust for adult material. We're ``sex drenched and sex phobic.'' Tisdale indicates that the fear starts with men, but that women can help fix it. ``Women guiding the sexual drive of men changes them, gentles the institutions men have made to cope with their feelings toward women.'' One area she sees women reinventing is pornography. The chapter on this subject is by far the most controversial and at times tedious. Coming down hard on anti-porn feminists like Catharine MacKinnon and Andrea Dworkin (even more than on the Religious Right), she argues for tolerance and maintains that the heterosexual nuclear family, reproductive legislation, and patriarchal society in general are likely to do more damage to women than any X-rated films. Finally, she reaches the unoriginal but hopeful point that sexual freedom contains the seeds of significant social change. ``The center will not hold...if radical sexuality works.'' Just about everything you always wanted to know about sex but were afraid to ask. Fluidly written, sexy, probing, personally revealing, and wise.