A sexy dab of cow dung behind the ears

The human awareness of smell is often dismissed as the weakest of our five senses, and this seems to be borne out by the paucity of our vocabulary for describing its wide range of sensations. Smell is certainly not a subject for academic study, unless you widen the definition to include pheromones and automatic sensors, which then makes it part of biochemistry or chemistry.

Yet this perception of smell may soon change, and olfactology could well be a discipline of the future. That would seem to be the opinion of the authors of Aroma, who pose an intriguing question: "We close this chapter, and the book, with a discussion of smell and postmodernity. If sight - panoramic, analytic and linear - is the sense of modernity, is smell - personal, intuitive and multidirectional - the sense of postmodernity?" Having read this remarkable book, I think the answer might be yes. Aroma is a fund of stimulating stories and has obviously been well researched. I found it much more enjoyable than Annick Le Guerer's Scent: The Mysterious and Essential Powers of Smell. Neither book is designed to tell you about the science behind smell; for that you must turn to Steve Van Toller and George Dodd's Perfumery: The Psychology and Biology of Fragrance or, better still, Michael Stoddart's The Scented Ape: The Biology and Culture of Human Odour. Nevertheless, Aroma is an excellent companion to both books, and places our least-understood sense in its historical and social context.

It has three sections: the first is a social history of smell from antiquity to the end of the Middle Ages; the second explores the ways in which smell is perceived in various cultures; and the third considers our modern attitude to aroma. The book begins with a surprising number of historical quotes that Constance Classen, David Howes and Anthony Synnott have culled from Greek, Roman and medieval writers, showing how perfumes and incense were used to proclaim power, invoke healing, disguise stenches or assist prayer.

Clearly scent had once been an acceptable subject for enlightened discussion, but then came the "olfactory revolution" at the end of the 18th century. At the time the stench of waste and excrement was blamed for epidemics of cholera and typhus. The answer was to clean up the offending mess rather than surround oneself with scents. The deodorising of towns and cities had begun.

To be without smell became praiseworthy, and this attitude also applied to people. Perhaps for a special occasion a woman might be grudgingly permitted to wear a little scent. For men it was strictly taboo. Later in Aroma, in a chapter entitled "Odour and power", this sexual difference is given a rather acrid feminist interpretation as an example of the exploitation of women by men, instead of being seen as the last vestige of a bygone age.

Today most people in the West still seek to minimise their own body odour through scrupulous attention to personal hygiene followed by the application of deodorants and perfumes. These are carefully chosen to give off the desired messages of social status, power or sexual attraction. We do it with Chanel No. 5 or Kouros; the Dassanetch people of Ethiopia do it with cow dung. The middle section of Aroma deals with the role of smell in societies around the world and provides lots of examples of how important it is, although misunderstood. The Dogon people of Mali believe they can hear and talk smells. They even carry this belief over into the realms of teaching, correcting dyslexia in their children by the somewhat unusual step of piercing the child's nose.

The Kapsiki people of Cameroon have a rich language of aromas and use this to describe their social structures. The Sever Ndut tribe of Senegal also map out their world using the language of smell, for example, tribal members are classed as fragrant, but Europeans are linked with monkeys and dogs and deemed to smell mainly of urine.

The third and final section is called "Odour, power and society". Here Classen, Howes and Synnott try to cover too much ground, ranging from the stench of Auschwitz to the "scent Wurlitzer" of Brave New World. Huxley used smell to contrast the artificial and empty world of a scientific utopia with the real world of the noble savage. Echoes of this attitude are to be found today in the approval of "natural" fragrances, but the truth is that we are already in the age of the scent machine, as shopping malls and hotel rooms show.

The final chapter of Aroma deals all too briefly with the "commercialization of smell" - the very choice of words revealing a faintly odour of disapproval. It is rather odd that the authors should adopt this attitude to the perfuming of public places, to create the right mood in people, when earlier in the book they accepted without question the incensing of temples and churches for similar reasons.

As a chemist I see the benefits of the artificial fragrance industry, not only in making the world a sweeter place but in saving species like the musk deer from extinction. I welcome olfactology as a post-modern academic discipline, but with a remit to encompass chemistry, biology, sociology and psychology. When that happens we will not only make scientific advances, but rediscover the emotional experiences of smell. That way we could enrich all our lives, and maybe even enrich the English language. Classen, Howes and Synnott have brought the day a little closer with their fascinating book.

John Emsley is science writer in residence, Imperial College, London.