A desire to lie to the people we lie with?

"You go to bed with someone you think you know, and when you wake up you discover that it was someone else - another man or another woman, or a man instead of a woman, or a woman instead of a man, or a god, or a snake, or a foreigner or alien, or a complete stranger, or your own wife or husband, or your mother or father." Thus Wendy Doniger introduces and defines the bedtrick at the start of this long, complex and thought-provoking study. At first, one is inclined to wonder whether there really are 600 pages to be written about something that presumably happens fairly rarely even to those who pride themselves on leading une vie mouvementée ; but it is in fact precisely the discrepancy between the bedtrick's rarity in fact and its commonness in fiction that prompts Doniger's investigation. We can tell all sorts of stories about sex, so why do we persist in telling stories about sexual trickery?

Doniger's attempt to answer this question is spread over ten chapters, each falling into two parts. The first part of each chapter describes one particular aspect of the bedtrick (for example, chapter one:

"How to commit adultery with your own spouse") and presents examples from an extraordinarily wide range of - loosely - literary sources, interspersed with a thoughtful commentary. The second part presents a more specific "approach" to the topic from one or another disciplinary viewpoint (philosophical, psychological and so on). The tidiness of this formal layout is to some extent illusory: the same theme may emerge in different places, a narrative may have to be referred to before it has been summarised and so on, and Doniger herself acknowledges that she "certainly do[es] not expect every, or perhaps even any, reader to read the book straight through".

Whether the reader reads straight through or takes a more appropriately devious route, he or she will pass through some unusual terrain. I now know things about the care of horses that I did not know before, not to mention garter snakes, the penal code in various American states, and the surprising life of St Eugenia; but above all I have learnt the plotlines of an astonishing number of Hollywood films. Doniger lists 195 items in the filmography that follows her bibliography; a section of the preface titled "The uses of insomnia" explains how she has acquired her encyclopedic knowledge of "the lowbrow popular movies that provide a rich compost for myths to grow in". Her previous books have rightly not hesitated to include films, comic books and so on among their sources, but here the "B" movies have actually become predominant by sheer weight of numbers. It can lead to some charming juxtapositions: on one page we start with the myth of Narcissus, progress to The Picture of Dorian Gray , and end up with Duck Soup , while another page takes us from Orlando to There's Something about Mary via The Little Mermaid and The Prisoner of Zenda .

Is it worth the journey? Certainly, Doniger is an author who combines the ability to make one think with the ability to entertain, and while this book may often be amusing, it is certainly not lightweight (in any sense). The stories that human beings tell have as much to say about their narrators as about the characters in them, and Doniger teases out a number of themes in and around the basic area of human sexuality - personal identity, the asymmetries involved in relations between men and women, the possibility of knowing another person and the possibility of knowing oneself. Given what she has to say, it is not surprising that the treatment is often more overtly feminist than in her previous writings.

Whether from a related sense of direct engagement with the subject, or because so much of the material comes from closer to home than usual, The Bedtrick is written in a noticeably personal style. Doniger has always had a somewhat jaunty way of expressing herself, but this book takes jauntiness to new extremes: "the usual double bind kicks in", "that ol' devil the double standard", "she got the drop on him", "In Cartesian thinking, identity must fish or cut bait", and many more. I am not sure that this is wise. For an academic book to be witty is definitely a good thing, but it must remain comprehensible to a wide audience, including those for whom English is a second language. I can imagine, for example, some Indian readers of The Bedtrick having problems understanding parts of it.

Indeed, the book sometimes seems to be addressed explicitly to a western, if not an American, audience. The dichotomies Doniger considers in the second part of chapter one, for example, are culturally specific, not universal (despite what she says, Sanskrit kama and prema do not equate to "sex" and "love"); she herself refers to "the mind/body world, which is to say much of the western world". Similarly, a consideration of physical beauty in "our society" is reinforced with a list of Hollywood stars, and elsewhere there appears the phrase "we all (ie we Anglophone readers)". In a book devoted to uncovering what myths (including myths from China, Japan and, of course, India) have to say about humanity, this seems a little strange.

Lastly, please, Professor Doniger, do not present the existence of chance homonyms in English as corroborative evidence for your arguments. The present book contains several such lapses: "split", "cleave", "ball", and a whole slew in the concluding chapter (including, mysteriously, "deceive"). It is easy to write that "it is only partly an accident of the English language that we lie to the people we lie with". OK, wise guy: tell us what else is involved.

John D. Smith is lecturer in Sanskrit, University of Cambridge.