‘To my amazement, there were no paintings . . . but only packages, piled one atop another to the height, say, of Picasso . . . And do you know what there was inside? Banknotes! Yes, sir, banknotes, the largest denomination that existed in France then, which was enormous.’ Christian Zervos is recollecting the day that Picasso took him, as a favoured confidant, to his vaults in the Banque de France. The fortune Zervos was allowed to glimpse in the mid-1930s had ridden out the Wall Street crash, and had been accumulating since before the First World War.

The epithet ‘triumphant’ in the title of the new volume of John Richardson’s magnum opus has a brash, swaggering ring: fittingly so. This is the tale of an extremely rich and famous man who came pretty near to doing whatever he wanted. The Picasso of the 1920s was physically strong and socially supple: he could charm the king of Spain, mesmerise Proust, shrug off Hemingway. He was news wherever he appeared and yet able to seal himself away in an expansive private freedom. One hand might distribute lordly largesse, the other remained clenched tight around those bundles of assets – ‘no different from the country bumpkin who keeps his savings sewn into his mattress,’ as Zervos remarked. Nothing impeded him when he ‘felt the need for a country house’, as Richardson puts it, or when he felt like taking his teenage mistress to amusement parks along with the son of his marriage. Six-year-old Paulo was already ‘sufficiently loyal to his father not to betray him to his mother’. The vastly successful and productive middle-aged Picasso may be a subject for awe; he does not invite compassion.

Richardson’s previous two volumes, taking Picasso to the age of 35, were more naturally engaging. The artist had to rise. He had to put behind him his hopeless father (‘an execrable painter’ specialising in anthropomorphic pigeons). He had to move in from the cultural margins, forsaking the amiably unchallenging Barcelona art scene for Paris. On the way, there were affecting deaths – his younger sister’s, that of his friend Casagemas – and there was Picasso’s first great love, Fernande Olivier, a character to whom Richardson particularly warmed. (One of the many amusements of his unfolding masterpiece has been the wilfulness of his likes and dislikes.) There was the bohemian camaraderie of the Bateau Lavoir studios in Montmartre, where Picasso shared opium and obscenities with Apollinaire and spent his furies on the Demoiselles d’Avignon. Above all, there was the heroic ascent of the ‘two mountain climbers roped together’, as Braque, his companion in Cubism, chose to remember it: a dialogue that seemed to change as much in art in seven years as had changed in seven centuries.

The outbreak of war in 1914 ended this, with Braque off to the trenches that also put Picasso’s other great friend and stimulus, Apollinaire, out of action – influenza finishes him off early in the present volume. Meanwhile, the market status of the war-exempted Spaniard heads inexorably upwards. As The Triumphant Years opens, in 1917, the rackety Bateau Lavoir with its mildew and mayhem has been left far behind, and the artist is checking into a grand hotel in Rome along with his new friend, the foppish, snobbish young Jean Cocteau. They are collaborating on Parade, a Ballets Russes production with a decor meant to ‘reassure the public that far from being pro-German or pro-Bolshevik or a fumiste, Picasso was not an iconoclast, as chauvinist philistines had maintained during the war.’ The time has come to behave like a respectable, plausibly responsible adult. Diaghilev’s ballet company provides him with an appropriate bride, Olga Khokhlova, a dainty St Petersburger ‘from much the same professional class as Picasso’s family’. Taking her to meet mother in Barcelona, Picasso plays to the home-town crowd by dashing off a mock-pointillist maja in a mantilla and receives a hero’s welcome. The couple return to Paris and set up residence in a plush and spacious Right Bank apartment, from which, over the coming decade, chauffeurs will transport them to their annual summer sojourns on the Côte d’Azur or at Dinard. We enter a world of 1920s highlife: fancy dress balls, beach huts and swimsuits, cocktails and jazz – at times Scott Fitzgerald is staying at the hotel down the road. Paul Rosenberg, Picasso’s canny, conservative dealer, backs up the big spending, encouraging him to trot out easy-on-the-eye charmers to keep Olga in Chanel couture.

Not long after the return to Paris, however, the need arises to bring another literary contender – André Breton – on side. ‘Picasso was loyal to Cocteau insofar as he needed a Rigoletto,’ Richardson writes, but ‘he also foresaw that Breton’s support might be more useful.’ And so begins a lengthy flirtation between the stocky celebrity and the riot-thirsty twentysomethings who launch the Surrealist movement in 1924. By that time, ‘Breton’s backing was all-important in the face of the possible but unlikely event’ of Picasso’s ‘leadership of the avant-garde being challenged by the iconoclastic Marcel Duchamp or that even wilder card, Picabia’. Picasso needs to stay a little above the fray, as befits his dignity (he doesn’t sign the young men’s manifestos), and he retains for the adoring Cocteau a tyrant’s fondness for his laureate; but it is crucial that he win the image wars and remain Mr Modern. There’s the stuff of mid-life-crisis comedy here: spats and plus-fours when Picasso walks out with madame in the haut monde, but ‘I like sausage and beans’ when he’s sidling up to the jeunesse. Moreover, for all his bullishness, he tends to flounder when it comes to the media: his one attempt at holding a press conference lands him in a mess when he blurts out some patronising remarks about Cocteau; nor can he stop a Paris newspaper publishing the indiscreet memoirs of his old lover Fernande under the title ‘When Picasso Painted Kitsch’.

But Richardson doesn’t go in for fun at Picasso’s expense. His biography, so ruthless when it comes to nailing everyone else, draws its integrity as well as its endless entertainment value from the fact that the author kept company with the painter during the last twenty years of the latter’s life, and thus writes as if he were looking his formidable old friend in the eye. Gossip holds them together like a shared bottle of wine – never pass up a chance for a good anecdote, but at the same time, keep faith. There will be much that is tricky and in need of unravelling if he is to regale his companion with his own life story, yet Picasso’s cause will always remain Richardson’s cause. Yes, he may seem to fall in with Cocteau’s reactionary cultural directive, the rappel à l’ordre, when in the late 1910s he brings in a new and very saleable product line of cohesive classical imagery to run alongside his chopped-up Cubism, but it must be understood, Richardson insists, that this is an ‘internal’ classicism, premised on a dynamic rather than a parasitic relationship with the past. Yes, the family-values cuteness of much of the work done for Rosenberg, not to mention the whole lifestyle it sustained, might seem to clash with modern art world values, but ‘the comme il faut impersonation was in part an elaborate joke,’ and Picasso was all the while slyly painting Cubist images that lent bourgeois subject matter ‘an edge that is both comical and Modernist’. Rightly understood, the name of Picasso and the cause of Modernism – which is to say, the cause of cultural virtue – never really grow apart: in this biography, their meanings are joined at the root.

But as he spins his bar-room yarn, the biographer keeps glancing over his friend’s shoulder. Does he like the look of the company around him? As it happens, no serious foes are lying in wait for Picasso in the 1920s. Among the Dadaists who might just have challenged his avant-garde supremacy, the ‘iconoclastic’ Duchamp is forsaking art for chess, while ‘wildcard’ Picabia pops up as his neighbour on the Côte d’Azur, another cocky bon viveur in Cuban heels: les deux Picas get on famously. Indeed, Picasso steals a pictorial trick or two from Picabia, a backhanded compliment he also pays many of the decade’s emerging stars. In Richardson’s close reading of the studio output, the subjects of such ‘Picassification’ range from Mondrian to Miró to Dalí. Arguably, each of them had been working under Picasso’s own broad shadow, and he is only borrowing back from those who stand in his debt. But meanwhile his artistic generation has virtually evaporated; he no longer has Braque’s companionship, and his old rival Matisse, painting unthreatening odalisques in Nice, looks to have quit the fray.

Instead of painters, Picasso is now moving among choreographers and composers, a grandee of the cultural elite. Richardson writes with feeling about his theatre projects, from 1917’s Parade to the 1924 Mercure – and draws on his own youthful experience as a ballet critic to illumine what’s now a relatively obscure part of the Picasso oeuvre. (He recalls that Parade’s original, phantasmagorically spectacular Cubist costumes just about survived, much battered, till 1955, then sank out of sight. We also read about Picasso decorating a rented garage with murals in 1924, then being forced to pay its irritated owner 800 francs to have them obliterated. Lost treasures of modernity.) Ballet brings Picasso into contact with people Richardson admires, such as Satie and Stravinsky – though this is a one-way communication. Much as the two respect him, the painter has a tin ear for classical music, and admits that ‘he had a terrible problem staying awake while their compositions were being performed.’ More to the point, to Richardson’s regret, the Parade project binds Picasso to Cocteau, a person for whom the biographer possesses a principled disdain. Taking pot shots at this clever, silly literary poseur becomes one of his favourite pastimes – an amusement evidently shared by all who came across him, Picasso included. Cocteau is a man who’s almost too scared to climb the gangplank onto a party boat, yet as soon as he’s aboard he’s running round yelping, for the sheer hell of it, ‘We’re sinking!’ – he really does cut a figure of Withnail-like poltroonery. Though, as with Withnail, his daft flamboyance proves irresistible and Richardson ends up chasing his story wherever it may head (through Catholicism and into opium addiction), handing him the mike for by far the liveliest account here of Picasso at work.

This preposterous flibbertigibbet may be the wrong kind of friend for his Modernist hero to hang out with, but at least he’s not a previous occupant of the writer’s own barstool. Time I declared an interest. The butt of Richardson’s most loaded derision throughout this volume is an English critic who paid court to Picasso some thirty years before Richardson and his onetime boyfriend Douglas Cooper moved in on the great man: namely, my grandfather Clive Bell. As a matter of fact, I don’t find it impossible to reconcile the snobbish and aesthetically obtuse ‘toady’ that Richardson delineates with the sagacious, genial old gent of my own rather dim childhood memories. Richardson never disguises the fact that he writes with a certain generational partiality and a distinct personal animus; each to his own. Slashing typecastings are integral to his style: ‘the loathsome Wildenstein’; the ‘notorious battle-axe – said by Cooper to have run a brothel’; ‘the creepy, unctuous seminarian Maurice Sachs’, who is one of the ‘fawning homosexuals’ in the fan club of that ‘rich, spoiled, homosexual narcissist’ Jean Cocteau. Tricky character, Richardson – at once out and a bit of a gay-baiter. Still, one hardly wishes him to be other than he is, and he so relishes having the last word. On Germain Bazin, a critic who became ‘one of the Louvre’s least distinguished directors’ after writing that Picasso’s ‘downfall is one of the most upsetting problems of our era’, he remarks: ‘Much the same could be said of Bazin’s rise to the top.’ Defensible statements, all of these, I dare say: still, it’s a little strange to hear Richardson berating Clive Bell for ‘cattiness’.

Faces, traits; this man’s indiscretions, that woman’s backstory: this is how Richardson’s world is structured, and what he makes it his business to know. And if he trusts to his own rapport with his hero, that is because he sees Picasso as very like him in these matters. When Richardson first set to work, nearly fifty years ago, he thought of ‘charting’ Picasso’s ‘development through his portraits. Since the successive images Picasso devised for his women always permeated his style, I proposed to concentrate on portraits of wives and mistresses. The artist approved of this approach.’ That explanation appeared in the introduction to his first volume, published in 1991, 18 years after Picasso’s death. And while the scope of the project vastly expanded during that interval, its procedures remain fundamentally unchanged 16 years further on. Richardson habitually unravels the artist’s purposes in terms of personas recollected in his imagination. For instance, the 1921 Three Musicians constitutes a rueful apology to the poet Max Jacob, an old bohemian friend banished by his prim new wife; the 1925 Woman with a Tambourine (Odalisque) is ‘a message to Matisse . . . a rebuke and tease’; while Mercure, the most radical of the ballet projects, is a riposte to both Cocteau and the Surrealists. But over and above such nods and winks to fellow cultural operators, any discussion of the work must, for Richardson, return to the question of women.

A question, needless to say, that Picasso’s marriage to Olga fails to settle. The pregnancy that brings them Paulo in 1921 sees him return to the Paris whorehouses, and four years later we find him roaming the late-night city with Michel Leiris, the brightest and most desperate of his Surrealist friends – ‘Picasso usually made out. Leiris usually failed.’ (‘He was only five foot three/but girls could not resist his stare/ Pablo Picasso/never got called an asshole./ Not like you!’ The Modern Lovers’ punk version of the legendary Lothario is at one with the biography.) Luck stays with him: in 1927 his fantasies become flesh when he picks up the 17-year-old Marie-Thérèse Walter. This voluptuous and compliant blonde becomes the secret divinity of his studio throughout the last third of this volume.

The narrative moves towards the grotesque antitheses of 30 December 1931, a day which Pablo and Olga pass at the Château de Boisgeloup, their new country house. We see the 50-year-old artist shuttling between a Christmas party, where his wife is handing out tea to gallerists and literati and toy cars and candy to Paulo and his friends, and the locked room on the second floor, where reveries of Marie-Thérèse’s Grecian head and full breasts morph into images of his own erection and where he is completing a hideous caricature of a screaming, maddened Olga stabbing his girlfriend to death. Olga must have been aware of the affair, Richardson infers, though the couple would not split till after this volume ends; also somewhere beyond that horizon lies the non-career of the drink and drug-corroded Paulo.

The antitheses are doubly convoluted. Upstairs is the good Picasso, by all familiar standards of art criticism. This year, 1931, is the ‘annus mirabilis’ (Richardson’s epithet) when his secret passion is expressed in a profusion of monumental, monstrously inventive canvases and exuberant sculptures: arguably, this is one of the high points of his career. By contrast, the company of the rectitudinous Olga has had an overwhelmingly depressive impact on his art. As Richardson comments, there is a horrid doomed ‘inevitability’ about their relationship from its beginnings in 1917: as soon as Picasso trains his pencil on the hopeful and engaging face seen in the Ballets Russes publicity shot that opens the volume, it turns into something stony and inert. He can render her integrity only in a ‘traditionally representative way’ – that is, until her jealousy at least makes her excitingly hateable. Did Picasso, like Proust’s Swann, somehow find himself marrying a woman who is ‘not his type’? Or is that to misunderstand him? As a devotee of the art, Richardson likes to claim that Marie-Thérèse ‘saved’ Picasso from ‘the psychic stress of his marriage and the bourgeois restraints that it imposed’. But surely that is sentimentalism. As an observer of the man, the psychic material Richardson has to account for includes an entirely self-willed craving for the bland, comme il faut anaesthesia of that marriage. The Picasso he describes spends much of his time revering the bourgeoisie in all its discreet charm and with all its suave complacency, and the days when he provides them with what, with any other signature, would be deemed kitsch are many.

Picasso gets what he wants. His women hardly function other than as projections of his will – Marie-Thérèse in particular, a sporty, no-nonsense modern girl who obligingly whizzes off on her bike whenever Olga’s car approaches the château and whose personality seems to defeat the biographer’s curiosity. Richardson, who enjoys scolding other art writers, takes Rosalind Krauss to task for claiming that ‘Picasso dreamed a type and then found her,’ a conclusion she arrived at by comparing the female figures in the sketchbooks drawn before and after he met Marie-Thérèse. ‘Fairy-story’ stuff, he reckons, discerning some earlier blonde, smuggled into the studio, who will account for the effect Krauss describes. But the larger truth stays with Krauss, when in The Picasso Papers (1998) she proposes that the artist provided himself with an ‘oppositional pair’ of female types – ‘the overt and the covert, the dark and the fair, the elegant and the voluptuous’. Quite as much as he portrayed one or other of these types, he shuttled between the two. Richardson himself suggests as much, discussing the 1928 Painter and His Model:

Once again the artist leaves us guessing as to the nature as well as the identity of the model. Is she a bust on a plinth or a live woman? If a woman, is she blonde-haired Marie-Thérèse whose profile is materialising on the canvas, a skinny, dark-haired Olga, or a blend of both? . . . There are of course no answers to these questions; there would be no magic if there were.

Focusing on such ‘magic’, Richardson’s description of the art moves beyond the naming game. Its most insistent refrain becomes ‘metamorphosis’. (Come 1930, Picasso gets to illustrate Ovid’s book on the subject.) The theme slowly picks up speed. At the volume’s beginning, Picasso, looking for fresh strategies to expand his repertory, is startled by Italy’s ancient marbles into thinking about scale. The quasi-classical pictures that follow aim for effects of massiveness, whatever their actual dimensions. Drawing on the examples of Ingres and Renoir, he dreams up figures suffused with and almost bemused by their own fullness. He bounces style off style, positing that these hefty armoires and his Cubist DIY packs both arrive by different means at an equal aesthetic completeness. In the mid-1920s, the internal dialogues of the studio are further complicated when Picasso dallies with the Surrealists. Their emphases on aggression and transgression, and on entangling forms and identities, help bring out aspects of an art that from the outset has been insistently sexual (as Richardson has always liked to point out). Picasso picks up Miró’s biomorphic sign language and runs off with it: he keeps managing to stuff more aesthetic fodder into his maw. The end of the decade sees him expressing all these impulses together as he expands operations to explore 3D mass itself, assisted in this move into sculpture by his old Barcelona friend Julio González.

The constants throughout this dauntingly complex multi-track progression seem to be Picasso’s bodily forms as they swell and subdivide, recombine and surge onward. It is as though they only incidentally attached themselves to individuals. Strangely, the most precisely evocative ‘portraits’ become those of the interiors or landscapes in which these figures are placed, with the vibrant colours of the Mediterranean littoral making a frequent appearance. Meanwhile, the Surrealist anthropologist Leiris offers the metamorphic artist an alluring new persona when he introduces him to the concept of ‘the shaman’. Richardson gives more shape to that role when he stresses tw0 of the equations that Picasso most cherishes. On the one hand, between the creative and the procreative, so that imagination and erectile flesh become one and the same; on the other, between himself and the divine. ‘I am God, I am God, I am God’ is the solipsistic formula with which this volume, like the two before it, concludes.

So the fairy story is very much Picasso’s own. He is alone, talking to himself: ‘Nobody has any suspicion of the solitude I have created around myself,’ as he told an interviewer in 1932. The manoeuvre of the secret affair is his way to reassure himself that he is free, though he depends on and is bound to his fame. An empty manoeuvre, part of a ricochet of fantasies without content, Krauss suggests in her sceptical meditation on Picasso’s central role in Modernism. What we see in the ‘annus mirabilis’ of his head/breast/penis extravaganzas is the flipside of his prewar creative high. If Cubism shook up pictorial signs to flutter in the air, freed from their familiar representational functions, they now shake down to a vacuous homogeneity. Wilfulness becomes all they denote.

I am here expressing some of my own scepticism, as I pored over the tale of a middle-aged artist trying to reinvent himself. I felt that I was reading not about passion but about arbitrary and pretentious transgression. Picasso might tell himself that he was fucking a teenager as some kind of black sacrament, for the sake of his art. (He got her reading Sade, and Richardson reckons he saw the affair as something like incest with a daughter.) But why should anyone buy this? Will some reality principle return, I started to wonder, with Vol. IV? The epilogue to Vol. III prepares us for the onset of the Spanish Civil War, the first occasion in Picasso’s life, Richardson argues, when he got round to concerning himself with politics; though we are now told that Richardson himself may never describe the painting of Guernica, let alone the artist’s eventual death at the age of 91: being 83, he has acknowledged that his great project will need to be completed by other hands.

He is reported (in an interview in the Observer of 7 October) as saying that ‘extortionate’ demands for reproduction fees have beset its publication with crippling difficulties. That may explain why there is a distinctly lower ratio of pictures to words here than in the two previous volumes. (Though not why the publishers have altered the new volume’s dimensions, as if to spite anyone wishing to line up all three on the shelf.) And this in turn may partly account for the rather distanced reaction to the art that I have just expressed: what is physically lacking as one reads, and what one needs again and again to see, is the sheer prodigality of Picasso’s studio, the inexhaustible inventiveness and variety of material effects it sustained. Richardson is as lively and shrewd a guide to the work as one could hope to find, but really his book asks to be read in Paris with the Musée Picasso round the corner for reference. In such a light the self-involvement would surely take on a fecund, rather than an arid aspect.

‘He is such an anxious man, always wanting to surpass himself,’ Julio González remarked, after the experience of working with him in the studio. ‘We should not forget that besides such masters as El Greco, Ingres, Gauguin and Cézanne, the principal influence on Picasso would be his own earlier paintings,’ Richardson adds. Folding back on himself, as it were listening for the echo of his own shouts as they bounced back from the studio walls, the protagonist of this story does not come across as a pioneer for any sort of public art movement, for all the claims made on him by everyone from the Surrealists to his biographer. The middle age of Picasso isn’t the place to look for an exemplary Modernism, whatever we might deem that to be. (And, amusingly, he despised contemporary architecture. He wouldn’t have a Modernist house built for him: would Michelangelo have been satisfied, he asked, if they’d offered him Renaissance furniture? No, he’d have wanted something authentically Greek! Such is the plateau where he saw himself standing.)

Nonetheless, Picasso does come across as a world. The breadth, not only of this loner’s protean art, but of his intelligence and curiosity, his generosities, his anxieties, his social manoeuvring – all bringing further lives into his ambit, all themselves brought to life by Richardson’s sprightly, buoyant prose – is stupendous. The depth, too: as images and friendships weave in and out of this glutted career, sometimes reappearing after decades offstage, the reader starts to experience effects that only the biggest novels can deliver. Even if these volumes were not a major factual resource for 20th-century cultural history, they would still engage us as an irresistible work of the imagination. There is room for such wonderful foolishness. Forget Picasso: here’s Brancusi (his sworn enemy, incidentally) and Cocteau’s idol, the charismatic poète maudit Raymond Radiguet:

They had both had enough of Cocteau’s shenanigans. ‘Let’s leave,’ Brancusi said. Off they went, with Nina Hamnett, to Montparnasse. The Dôme was about to close – just time to buy cigarettes. Brancusi suggested they go to the Gare de Lyon for a bouillabaisse. It was no good, so they decided to take a train to Marseille as they were, without luggage and without Nina. The Marseille bouillabaisse turned out to be no better. Radiguet exchanged his dinner jacket for a sailor suit, and after a night of debauchery in the vieux port, they boarded a boat for Corsica. The men of Ajaccio seldom let their women out of the house, so Radiguet and Brancusi departed for the mountains, where all they found were hags in black herding goats. They ended up in a vast unheated hotel, where they stayed warm by consuming quantities of Corsican brandy. Heaven knows what else they got up to.

I bet Richardson has a pretty good idea.