John Ruskin: No Wealth But Life
John Batchelor
Chatto & Windus, £25, 369pp

John Ruskin: The Later Years
Tim Hilton Yale University Press £20, 544pp
Buy it at BOL

Even by the remorseless standards of the 19th century - the 26 volumes of Thackeray's collected works, Dickens somehow managing to combine writing novels with editing a weekly magazine - Ruskin's fecundity can still come as a shock.

In his mid-50s, 30 years into a career that had begun in 1843 with the first volume of Modern Painters, he continued to file research projects with a raptness that verges on mania. Work in progress in 1875 included a history of 15th-century Florentine art in six volumes, a history of pre-Christian Attic art in three, serial lives of Scott, Xenophon and Hesiod and a "general description of the geology and botany of the Alps, in 24 volumes". Neither of his latest biographers, John Batchelor and Tim Hilton, offers a definitive total, but the final computation can't be much under 250 items.

Equally difficult, too, not to imagine that this extraordinary torrent of print, an endless inky fountain of lectures, reflections and articles, wasn't somehow a replacement for something else - that the fervour with which Ruskin put pen to paper compensated for the dramatic fractures and absences of his emotional life.

As both Batchelor and Hilton show, the latter in relentless detail, Ruskin's acquaintance was a Victorian Who's Who, taking in everyone from Turner to Swinburne, the pre-Raphaelites to William Morris, and yet his solitariness pulses away like a lighthouse beacon. Simultaneously indulged and kept up to the mark by wealthy parents, whose roots in "trade" gave him an edgy provincialism that he never quite shook off, he found it perfectly natural that his mother should follow him to Oxford.

She despatched wonderfully snobbish letters home about his well-born chums: "The only thing that occurred during the lecture that will please you particularly", she informed Ruskin senior, "was that Ld. March and Ld. Desart came and placed themselves by John, and Ld. March having forgot to bring a pencil asked John if he could lend him one."

Other pencils - one pushes the metaphor because it seems so intimately bound up with Ruskin's creative sense - were conspicuously short on lead. The marriage to Effie Gray, first picked out as a pre-pubescent 12-year-old, was never consummated (it says something for Ruskin's detachment that when Effie went off with J E Millais, who she met during the sessions for her husband's portrait, Ruskin insisted that the picture be completed).

Subsequently, he continued to exhibit the trademark Victorian weakness for young girls and even in old age was capable of proposing marriage to the 18-year-old Kathleen Olander (Miss Olander prudently declined). Certainly Ruskin was a passionate man - no one who reads a letter of his could think otherwise - but the passion, as Batchelor notes, was largely reserved for Venetian architecture.

It would be odd if some of the evasions and concealments of the life didn't cross over into the work. Technically he was a mid-period Romantic ("Derwent Water", the poem penned at a precocious 11, is a creditable piece of pastiche Wordsworth) keen on Carlyle, but capable of giving his absorption in art an intensely practical focus.

Naturally enough, this being the 1840s, this process began with a defence of Turner - Ruskin's failure to write Turner's biography must rank as one of his great omissions - but as early as half way through his 17-year stint on Modern Painters he was stressing art's social basis and its function in conveying social truths. As Batchelor points out, this kind of thing had serious implications for the view he took of Victorian culture as a whole. If art had any merit it had to be the product of a "moral" society; at the same it had to reflect a complete world, something that even George Eliot and Balzac - whose narrow realism he deplored - were incapable of achieving.

If all this sometimes makes critic Ruskin sound like the last of the premodernists, vainly holding on to a centre that was fraying at the edges, then it gives social reformer Ruskin a lasting resonance. At the heart of a work like The Political Economy of Art is a simply held belief that art is the expression of human delight in labour. Again this had far-reaching implications for the whole Victorian concept of "betterment". It implied a society that was static, or perhaps organic, rather than linear.

Amid the anthills of Victorian social advancement, "not only is the natural discontentedness of humanity developed to an unheard-of extent, whatever a man's position, but it becomes a veritable shame to him to remain in the state he was born, and everybody thinks it is his duty to be 'a gentleman'". This is a romantic view of work in excelsis. Plenty of writers have laboured the connection between wealth and power: few have done quite so much to set down its effect on the average human spirit.

Thereafter the path led to F D Maurice and his working men's colleges, William Morris, social experiments and even an end-of-century mock-medievalism, steamrollered by the late Victorian machine age - as, of course, it was always bound to be.

Though the extraordinary feats of production were kept up nearly to the end - the autobiographical Praeterita was unfinished at his death - Ruskin's last years were a decline. Hilton offers an awesome recreation of the pressures to which the 60-year-old savant was subject: the relationship with Rose la Touche ending in tragedy ("the woman I hoped would have been my wife is dying"), a defence of the freethinking Bishop Colenso turning into an assault on the whole episcopal hierarchy.

Again, one has the feeling - which is Hilton's point - that Ruskin's real targets go beyond the bench of bishops, and the person being defended is himself. By the final quarter of his life he was becoming out of date, and he knew it. Late-Victorian aesthetics, which in a sense he had helped to create (art for art's sake and the rest of it) were anathema to him.

Whistler's libel suit of 1877 - Ruskin had remarked of "Nocturnes" that he "never expected to hear a coxcomb ask 200 guineas for flinging a pot of paint in the public's face" - was an unhappy symbol of the new aesthetic divides. In the end Whistler was awarded a derisory farthing's damages, but the real loser was Ruskin. Meeting him in 1880, the 18-year-old A C Benson noted that he "seemed to have come from a different century". Worn out and mentally unstable, he still managed to survive a further 20 years.

John Batchelor's book is an excellent short study, keenly alert to the social and political environments in which Ruskin found himself, if sometimes a bit confusing chronologically; Tim Hilton's the second part of a prodigious month-by-month pursuit. Allowing for the differences in scale and treatment, their message is broadly the same.

Critic Ruskin may have been the last premodernist, social-theorist Ruskin the last amateur in an age of specialists, and yet, compared to the social and aesthetic counter-terrorists of the 1880s who supplanted him, he looks bang up-to-date. What, for example, would Ruskin have had to say about the Millennium Dome or the stakeholder economy? Retreating to the narrower world of books, I remember the late Sir Kingsley Amis once claiming that the writer's only duty was to literature. Ruskin, you suspect, would have corrected this to "the rest of humanity". And Ruskin would have been right.