But Art Nouveau, with its characteristic curving lines and air of langorous, sexually charged mystery, defines the fin-de-siecle era exactly. This was an in-between period, a time of optimism and renewal as the door shut on the bad memories of the great industrial century, and the seismic shocks of the new century had yet to be felt, beyond a non-specific unease at something ugly beyond the horizon. Idealism, utopianism, socialism were growth industries, yet there were still only whisperings of the other important isms - modernism, futurism, functionalism, rationalism. Art Nouveau can seem pretty wussy compared with these. Art Nouveau did not care to engage with the machine gun or the steam hammer. It sidestepped modern life. It was all to do with fragile beauty. It was escapist. And we British, as the V&A's appropriately sumptuous new show makes clear, both helped to inspire it, and contrived to reject it.

In short order in the late 19th century we had already had the Pre-Raphaelites, the Arts and Crafts movement of Morris and Webb, the artistic diktats of John Ruskin, the Aesthetic Movement associated with Oscar Wilde and James McNeill Whistler and Aubrey Beardsley. Fold these ingredients together and you have the makings of something potent and different. Art Nouveau was nothing if not eclectic, capable of drawing on everything from Japanese prints to Transylvanian folk art. Voraciously it also toked heavily on the perfumed smoke of British artistic idealism. Pre-Raphaelite Woman - aloof, tragic, implausibly beautiful, damnably sexy - became Art Nouveau Woman, who was all that and who also sold cigarettes and beer. Because Art Nouveau, though it had its high artistic moments - Klimt, Munch - was a very, very, commercial style. When we think of it we are as likely to think of the advertising posters of Alphonse Mucha, adornment of a million dreamy girl student bedsits. It will doubtless come as a surprise to many at this show to find that Mucha did jewellery and sculpture as well.