Men's fragrances have evolved from a rare commodity into a billion-dollar industry

In the glorious days of ancient Rome, men very seldom bathed themselves in any kind of fragrance, unless as a vital sacred ritual and only rubbed on or poured on against ailments. Even the great philosopher Plato believed that smell could only be "defined relatively, in terms of other smells". But things have shifted. The whiff that accompanies a gentleman is not only a billion-dollar industry with extreme marketing budgets and celebrity endorsement, but also an artful caress of expression.

Smell is essentially primal and, according to Barbara Herman, author of Scent and Subversion: Decoding A Century of Provocative Perfume, "it penetrates the oldest part of the brain - the rhinencephalon - where the limbic system, or seat of our emotions and memories, resides". This goes a long way towards explaining why a whiff of certain foods sends us spiralling back to visions of our childhood, or why particularly intense perfumes, such as Versace's Oud Noir or Tom Ford's Café Rose, are unforgettable - whether or not you're a fan of the aroma.

British perfumer Roja Dove calls scent "the most profound of all the senses" as he believes that each odour stimulates the synapses located in the most primitive part of the brain, releasing hormones which govern every bodily action. "Scent works like a cat-burglar," he says. "It [intrudes] into our minds ... unlocking the floodgates to memory and emotion."