The Origins of Sex: a History of the First Sexual Revolution
Faramerz Dabhoiwala
Allen Lane, 496pp, £25

Let's talk about sex. Whether celebrated, reviled, cherished or repressed, it presents a huge challenge for the historian: is there any subject people lie about more? How can we know what our ancestors really thought about sex, rather than what they boasted about in pornography or thundered against in sermons?

Perhaps that's the reason, as Faramerz Dabhoiwala notes sadly in the introduction to The Origins of Sex, that no one has attempted a sweeping history of 18th-century monkey business since Lawrence Stone and Keith Thomas 30 years ago. "Since then, the history of sex, though increasingly popular, has also become ever more narrowly specialised," writes Dabhoiwala. "The intense focus on the trees, rather than the wood. . . [has] overlooked the world-changing cultural shift that was so obvious to earlier, bolder scholars."

There follows a series of meditations on some of the ways in which attitudes to sex have changed. Dabhoiwala likes his 18th century the way I like my Martinis: long. It begins here in the mid-1600s and eventually peters out with those censorious Victorians. He traces several undeniable cultural shifts: the spread of erotic literature thanks to mass print culture and rising literacy; the idea of sex as "private" (having a bed you share only with your sexual partner is a very recent invention); the burgeoning idea that prostitutes might be victims of circumstance rather than greedy trollops; and the creation of "sexual celebrities" such as the mistresses of kings.

Perhaps the most shocking revelation is quite how casually some of our best-loved writers regarded rape and sexual assault. Samuel Richardson's treatment of Clarissa Harlowe - whose rape is the central act of perhaps the central text of British 18th-century literature - can be better understood against the context of a society in which women were presumed to enjoy being assaulted.

Samuel Pepys repeatedly forced himself on the wife of his subordinate William Bagwell, switching to Franglais to recount how he "had mon plein plaisir of elle" and "had sa compagnie, though with a great deal of difficulty", once injuring his finger in the course of his struggles. And here's Henry Fielding, translating Ovid: "Perhaps she will scratch, and say you are rude: notwithstanding her scratches, she will be pleased with your getting the better . . . [Keep going] to your journey's end! The girls may call this perhaps violence but it is a violence agreeable to them."

Although the individual chapters are fascinating and Dabhoiwala's breadth of reading and sourcing are impeccable, what stumps this book is the problem the author identifies at the start. A "world-changing cultural shift" is hard to catalogue in 490-odd pages, without resorting to either hopeless generalisations or endless caveats. "I have highlighted the themes and time frame that seemed to me most evidently important," Dabhoiwala notes in the epilogue, "and concentrated on the views of the educated middling and upper classes of the period." Earlier, he acknowledges that he is primarily writing about early-adopter London. Women's voices are also often absent, despite their dominant contribution to the novel genre. (Perhaps my favourite passage in the book is a section on Richardson's theoretical enthusiasm for polygamy, which archly concludes: "Mrs Richardson's views are not recorded.") Similarly, Jeremy Bentham's unusually enlightened writings about gay sex are offered as evidence that: "The new approaches to human nature, law and ethics that had advanced the idea of heterosexual liberty also made it increasingly possible by the later 18th century to defend homosexual freedom in equivalently wide-ranging, cogent and dispassionate terms." Two pages later, however, we are informed: “It is notable that Bentham never published these proposals, though he repeatedly considered doing so."

Dabhoiwala finishes by considering the backlash by the Victorians and the subsequent re-loosening of knickers in the 20th century. Yet, even now, other countries execute gay people, prostitutes and adulterers, and every Republican presidential debate seems to roll back access to abortion further in the US. Whether our second sexual revolution will last longer than our first is far from certain.