Pop psychologists love smell. Smell is supposedly about sex and deeply buried memory, a sense that bypasses the rational mind, thwarts all efforts of language to describe it, and reaches sneaky neural wiring directly into regions beyond thought. It’s the fondest hope of every perfume firm that the psychologists should be right, and that human beings should be sniffing each other to say hello and see who’s been where and with whom. Psychology is supposed to be a science, and science makes profits predictable.

Unfortunately for the profits, perfume is an art, not a science. Tocade is not a better fragrance than Dior Addict because it better approximates the mix of odours released by a fertile female; Tocade is better than Dior Addict because it’s more beautiful. The varieties of beauty in art are not irreducibly animal and ineffable. Somebody puts these things together with skill and intention. Perfumes have ideas: there are surprising textures, moods, tensions, harmonies, juxtapositions. Perfumes seem to come in various weights and sizes, to have different personalities, to wear different clothes, to worship different deities.

Some perfumes are facile and some are complicated. Above all, some are better than others.

The fact is that this stuff is worth loving. As with the tawdriest pop melody, there is a base pleasure in just about any perfume — even the cheapest and the most starved of ideas — that is better than no perfume at all. It decorates the day. It makes you feel as if the colours of the air have changed. It’s a substitute for having an orchestra follow you about playing the theme song of your choice. Perfume is wonderful.

Strengths and weaknesses

Pure perfume is dissolved in a solution of 98% alcohol and 2% water, the preferred solvent. Different concentrations of perfume oil are sold under different names: eau de toilette (EDT) is about 10% perfume oil, eau de parfum (EDP) somewhere between 15% and 18%, and parfum (also known as extrait) 25% and higher. Occasionally, just to maintain the mystique, fragrance houses spring strange names on you: parfum de toilette is generally the same as eau de parfum; body sprays and eau de cologne are usually lighter than eau de toilette; and for everything else you will probably have to ask — and get a wrong answer.

What we make of ...

TOCADE by Rochas FIVE STARS

Rose vanilla It is still far too early to sum up Maurice Roucel’s achievements, as he regularly seems to come up with new wonders, but I would be surprised if Tocade did not figure among his top three perfumes even 20 years from now. When it came out in 1994, Tocade went against the grain of the two main tendencies at the time: the outrageous and the apologetic, exemplified respectively by Angel and L’Eau d’Issey. Tocade’s simple, compact prettiness felt so deceptively familiar that many failed to grasp how original it was. It was a floral oriental among many. It did not use any weird, novel molecules. It made no mystery of its intent, which was to have some harmless fun with rose and vanilla, perhaps the two materials most frequently used by perfumers. And yet: if the devil is in the details, so are the angels. Tocade’s rose was unlike any other, with the iridescent gleam of nail varnishes that change colour depending on viewing angle. The vanilla, too, was weird, perfectly judged between ice cream, smoke and candyfloss. Everything, from the juicy top notes to the butter-cookie dry-down, meshed together perfectly, gracefully, happily, to give a perfume with vivid eyes, a ready laugh and pretty dancing feet. LT

JUICY COUTURE by Juicy Couture FOUR STARS

Tuberose floral Far classier than the wonderfully trashy packaging would lead one to suppose, this is nicely crafted — one of the best in the genre. LT

JUST ME FOR MEN by Paris Hilton ONE STAR

Sad sack Ideal for her sort of guy. LT

Extracted from Perfumes: The Guide by Luca Turin and Tania Sanchez (Profile £20). To order it for £18, call The Sunday Times BooksFirst on 0870 165 8585 or visit timesonline.co.uk/booksfirst.perfumestheguide.com

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