Sex is our oldest obsession. For as long as we've been doing it, it has been used as a mark of decline and a measure of progress. It has been at the centre of rituals and responsible for revolutions. We make money from it, hide behind it, prohibit and promote it. It relaxes us, revolts us, hurts us and helps us. But whatever we think about it, however we do it, it defines us. Mark Doty examines the phenomenon of being a gay man who once married a woman rather than come out of the closet. Brian Chikwava recounts the history of revolution and sexual liberation in Zimbabwe. Jeanette Winterson offers up a wickedly irreverent modern-day myth about sex and the gods, and Jennifer Egan contributes a piece of fiction about a strung-out, disillusioned music producer. Other contributors include Herta Muller and Dave Eggers and Marie Darrieussecq . We're also pleased to present a previously unpublished piece of prose by the late Roberto Bolano.