He’s Brash. He’s Bold. He’s . . . Young Picasso. : A LIFE OF PICASSO: Volume One, <i> By John Richardson (Random House: $39.95; 521 pp., illustrated)</i>

How jealous was Pablo Picasso? Pablo Picasso was so jealous he would lock his mistress Fernande Olivier in the studio when he went out on errands. Once there was a fire on the floor above, in the legendary ramshackle Montmartre building known as the Bateau Lavoir, while Fernande was locked in. That can’t have been pleasant for her. She was the first great love of Picasso’s life, an honor that getting shut up like a pet in heat seemed to go with.

No policy of confinement is reported apropos of Picasso’s earlier girlfriends Rosita, Odette, Germaine, Blanche, Madeleine and Alice, or his innumerable lesser liaisons. But then, he was still of a tender age: just 25 at the close of this first volume of John Richardson’s promised three-volume life, which leaves the artist in 1907 facing a large blank canvas. (Volume 2 will thus commence with what happened on that canvas: a picture of five prostitutes, Les Demoiselles d’Avignon , that set off an explosion in Western culture from which debris still is raining down.)

To get it out of our system, I have begun with maybe the most sensational item of gossip in the book at hand, which in general is not that kind of book. Besides a majestically researched, lucidly written, all-but-definitive biography (lacking only a few documents still inaccessible), it is even a spoilsport book on the whole. Groaning shelves of Picasso hagiography, from the sensitive devotion of a Roland Penrose to the panting trash of an Arianna Stassinopoulos Huffington, have awaited the correction that Richardson, who befriended Picasso in the artist’s later years, provides with sober efficiency. The author often seems less to be telling than to be un-telling, scuttling myths left and right.

Was little Pablo a Mozart-like prodigy? No. (After unremitting practice starting in childhood, he became startlingly good in his late teens, an early but not unheard-of flowering, and museum-quality only in his early 20s.) Did his father, a mediocre painter of pigeons (no kidding), succumb to an Oedipal coup d’etat by handing his brushes to 13-year-old Pablo and swearing never to paint again? Uh-uh. (Sad old Don Jose kept painting for many years thereafter.)

After Gertrude Stein sat some 90 times for her famous portrait, did Picasso, alone in the studio, suddenly repaint the great face in one fell swoop? Not bloody likely. (Considerations central to Picasso’s stylistic development argue for an extended labor.) Did the great anarchic writer-artist Alfred Jarry give Picasso the pistol with which he would scare off pestering German art-lovers? Dream on. (The two men never met, though Jarry’s gun and the gunplay check out.) Was Picasso once so cold in Paris that he burned a mass of drawings? “Sheer fantasy!” remarks Richardson.

Richardson is hardly sour on his subject, whose Demoiselles he calls, defensibly but with more emphasis than seems really necessary, “the most innovative painting since Giotto.” But the writer’s commitment to truth keeps setting him at odds with cherished fables of Picasso’s genius, most of them traceable to the artist himself. The effect is to give a book that is a labor of love a deflating tone. (I know I feel deflated, having long believed all those stories. Now I miss them!)

Richardson frequently seems to be reminding himself, and thereby us, that Picasso’s work is what makes him important, not his persona and certainly not his often charming but just as often dastardly person. Picasso could be vain, cruel and grossly selfish in his time off from being--whatever this may say for our century--by a long shot our century’s main artist. Richardson’s strongest suit is a running analysis of Picasso’s stylistic evolution that makes El Greco, Goya and Gauguin as vividly present in the book as any friend or mistress.

Born in Andalusia, to whose macho culture Richardson attributes the artist’s lustful and aggressive (though also strangely sly and shy) temperament, Picasso was what you could call fast-tracked as a painter. From early on, he received doting encouragement from his father and a mostly female extended family. Picasso was made, in other words, and not born, much as it pleased and--by haloing his self-centeredness with divine right--served him to pretend otherwise.

By the time he enrolled in the School of Arts in Barcelona at age 14--not, alas for the legend, after making any extraordinarily short work of the entrance exam--his vocation was set, as was his knack for enlisting the self-sacrificing aid of women and men. He soon was a cock of the walk on Barcelona’s lively Bohemian scene of the 1890s, with his first circle of sycophantic cronies and his first mistress. What follows is the tale of his triumphs over one milieu, influence, rival and woman after another.

It wasn’t always easy, especially when it came to breaking into the pitilessly resistant art world of Paris--a struggle fraught with poverty and humiliation. (Lest you suffer painful nostalgia for the Bateau Lavoir, consider that on a basement landing of that firetrap was “the one and only toilet, a dark and filthy hole with an unlockable door that banged in the wind, and, next to it, the one and only tap. This provided water for some thirty studios . . .” The undoubtedly sentimental pictures of human wretchedness in Picasso’s so-called Blue Period, which he would later scorn, are not without truth to his experience. But however much he suffered, Picasso usually could find someone else to suffer even more for his benefit. Always there was a poet in the picture, for instance--feeding the artist stimulation and typically ending up the worse for wear.

Such was the tortured Catalonian poet Casagemas, whose end in 1901 is told in one of Richardson’s more cinematic passages. While dining with friends in Paris a month after being brushed off by Picasso, who was in Spain, Casagemas drew a pistol, “yelled at Germaine (his girlfriend, later Picasso’s), ‘ Voila pour toi !’ and fired.” Thanks to a bystander deflecting the barrel, “the bullet missed, but the explosion knocked Germaine to the ground. Concluding that he had killed the woman he loved, Casagemas put the gun to his head, and crying out ‘ Et voila pour moi !,’ shot himself in the right temple.”

Picasso felt guilty about Casagemas’ suicide, which is not to say he was devastated. Like seemingly every other emotion he experienced, his guilt went directly into the furnace of his art, inspiring a series of images of the poet alive and dead that culminated in the Blue Period masterpiece La Vie . His wholesale consumption of other souls gets monotonous, plus appalling. (Richardson writes: “It must be painful, Picasso would say with more pride than guilt, for a woman to watch herself transformed into a monster, or fade from his work, while a new favorite materializes in all her glory.” It’s a relief when Picasso meets his match in Guillaume Apollinaire, Gertrude Stein and Henri Matisse, whose personalities were quite as powerful as his own.

“Harlequin Trismegistus” (Thrice-Great Harlequin), Apollinaire dubbed Picasso, jump-starting the mythification of the artist that has been a 20th-Century industry. Thus do we leave the little Andalusian preparing, with some help from his friends, to become a colossus.

It will be interesting to see how Richardson in subsequent volumes copes with the increasingly blinding aura of Picasso’s fame. On the evidence of this fine start, he will do so astringently, keeping in firm perspective both the artist we revere and the man we might like to kick in the pants.