What else is new? He was writing, as it happens, about the last decade of the 19th, not the 20th century. He goes on - and here is the difference - to record that 100 years ago, alongside this widespread pessimism, there was also a remarkable ferment of innovation, 'with much talk of the New Drama, the New Woman, the New Journalism, the New Imperialism, the New Criticism, the New Hedonism, the New Paganism' and so on.
The foolish habit of endowing the decades as they pass with a stereotype is stronger than ever. The Twenties were the decade of political reaction and social pomposity, as well as the age of the flapper and the cocktail, and most of the same people who had been conformist in the Fifties went on being conformist in the Sixties.
This decadism has led the 1890s to be type-cast as 'the Yellow Decade', as if all that was happening in London in those 10 years was the coronation and fall of Oscar Wilde and the publication of the Yellow Book. Long ago E F Benson disposed of that error in a memorable burst. 'Before the dawn of the Nineties, the old idols had been quite toppled over,' he wrote. 'The attempt to demonstrate that there was now marching out of the Bodley Head under the flying flag of the Yellow Book a band of Aprileyed young brothers singing revolutionary ditties and bent on iconoclasm is disastrous to any clear conception of what was going on.'
The Yellow Book, Benson points out, was 'a respectable, almost highbrow organ'. It included articles by such respectable near-fogies as Edmund Gosse and George Saintsbury, , and the illustrators, besides Beardsley, included John Singer Sargent, Wilson Steer and no less a Victorian than Sir Frederick Leighton.
A few dates remind us of the extraordinary creativity and variety of the London 1890s in literature as well as in science. In 1890, for example, Oscar Wilde published The Portrait of Dorian Gray, and Kipling The Light that Failed. The next year, Conan Doyle published The Adventures of Sherlock Holmes, George Gissing published New Grub Street and Thomas Hardy finished his sport with Tess. . In 1897 J J Thomson discovered the electron, and by 1900 Max Planck had elaborated the quantum theory.
Karl Beckson brings that London of 100 years ago alive with a series of deft sketches. He is specially good on the cult of sexual 'inversion' which motivated such different talents as those of Wilde himself, Swinburne, John Addington Symonds, the historian of the Italian renaissance, and, in repressed form, Henry James, Edmund Gosse, Gerard Manley Hopkins and A E Housman. He demonstrates that The Importance of Being Earnest was a double pun: 'Earnest' was a euphemism for 'Uranian' or homosexual before Wilde wrote the play.
He pursues curious avenues of the Uranian world, which had been driven underground by the notorious Criminal Law Amendment Act of 1882. We eavesdrop, with some embarrassment, on Edward Carpenter's desire for 'the thick-thighed, hot, coarse-fleshed young bricklayer with a strap round his waist', and E M Forster's desire to 'love a strong young man of the lower classes and to be loved by him'.
Not that the Uranians had it all their own way. The 'purity crusaders' led by Laura Ormiston Chant failed in their campaign to close the 'promenades' at London music halls where the more expensive prostitutes loitered; 20 years later it took a world war and the Bishop of London to succeed where Mrs Chant and her friends had failed. So fleshly a poet as Arthur Symons, arch-champion of the French Symbolist poets, described in flaming verses his pick-ups from the promenades and the pavements. The Pall Mall Gazette didn't approve. 'Every woman he pays to meet him, he tells us, is desirous to kiss his lips; our boots, too, are desirous, but of quite another part of him, for quite another purpose.'
It is striking how intelligent, red-blooded and controversial the journalism of the 1890s was compared to the spiritless ideological tub-thumping and pop sociology of 100 years later. The new mass journalism was challenged by periodicals like the Hobby Horse, the Dial and the Yellow Book which achieved a remarkably high standard of literacy and seriousness.
Karl Beckson has brought this vigorous yet troubled world to life in all its ambiguities and contradictions. He describes the injections of vitality into London in that period from abroad: notably from Ibsen, Nietzsche, Verlaine and Zola. He traces the struggle of the New Woman, from the journalistic controversy of 1888 over the 'Marriage Question', to the work of such proto-feminists as Olive Schreiner and Edith Rees. He also shows that while many women, from Queen Victoria to Margot Asquith, opposed women's rights, many of the most talented male writers of the 1890 generation, including Hardy in Jude, Kipling and H G Wells, addressed themselves in challenging ways to the relationship between the sexes and, for the first time since the 18th century, dealt frankly with both male and female sexuality.
In this and other ways, the 1890s, so far from being a decade of pallid decadence, laid the foundations for the explosion of modernism in the first quarter of the 20th century: Nostromo, The Portrait of a Lady, The Second Coming, Ulysses. It is notorious, though, how many of the great achievements of modernism were raised by writers in English who were not English.
Already, 100 years ago, many of the most gifted of British writers were retreating into the past, or the exotic, or the mid-market, leaving the richest harvest of their own language to be gathered in by literary immigrants. At least, in the Nineties, literary London was a busy enough beehive of ideas, reputations and rewards to attract guest workers of prodigious talent.