BOB Dylan is a myth. Conceived and named by a rambling Midwest youth, Dylan was destined to become the Spokesman of a Generation and condemned in some diabolical pact to pay for this by embarking ultimately on the seamless odyssey that is the Never Ending Tour.

He is a legend that makes cautious men form rash assessments: ''He is a better poet than Byron.'' He can make dry professors become lubriciously excited. He is a force that makes fans, particularly male ones, resort to a lazy stereotype. Those of us who do not index our CDs alphabetically or cross reference them by genre, those of us who know Jimmy Johnstone was a great player but have no interest in exactly how many goals he scored or appearances he made have an uncharacteristic need to be obsessive about Dylan. We become completists in chasing down his musical output, sweating over that missing set from the Barrowlands. We hang on his unspoken word. Dylan talks to his audience as much as he talks to the press. He is as loquacious as Harpo Marx with laryngitis.

It is this that makes this publication such an event. First, though, there is a warning. Robert Zimmerman has a talent for invention. It is, after all, his genius. ''Life is more or less a lie,'' he says on the second page.

The myth of Bob Dylan initially included claims that he was an orphan who arrived in New York by hanging on to the underbelly of a freight train. Bob puts us straight in Chronicles that this was but a story. Robert Zimmerman arrived in New York on some unspecified date in the 1950s in a four-door sedan, a '57 Impala. He rode over George Washington Bridge and got out the car. He pulled up his collar and faced the biting wind. Zimmerman was dead. Dylan headed into Greenwich Village and fame: ''Now destiny was about to manifest itself. I felt like it was looking right at me and nobody else.''

Thus the first section of the first volume of Chronicles (Dylan has promised three) ends. In a perverse Dylanesque fashion this seems as good a place as any to interject with observations about what the book covers and what it does not.

Chronicles is made up of five chapters or tracks. The temptation to compare it to an album is irresistible. The chapters are like songs, written with an obvious lyricism and containing subject matter that can sweep from the historical to the personal. It is not a chronological account. The first and last chapters, Makin' Up the Score and River of Ice, are centred on Dylan's first steps in New York.

The Lost Land is an obituary for a homely America and a nod to the influences that were informing both Dylan and a continent in the second half of the twentieth century.New Morning tells of the private anguish that fame brought, with intruders scuttling over his roof in Woodstock and his fellow musicians looking for him to lead them out of the wildnerness. Robbie Robertson of The Band asks him: '' Where do you think you're going to take it?''

''Take what?'' replies Bob. ''The whole music scene,'' says Robbie. This responsibility seems both to spook and anger Dylan. His most powerful protest is that he is not a spokesman for anything. The album New Morning and a trip to Nashville provide the removal of this unwanted burden.

Oh Mercy tells of the making of that album and his collaboration with Daniel Lanois. This was seen as Dylan's resurgence to form. He feared he was becoming an ''old actor fumbling in garbage cans outside the theatre of past triumphs''. Oh Mercy, Lanois and New Orleans brought him out of this creative torpor.

All the chapters are imbued with a twanging Americana, a spirituality that is New Age and Old Testament and a series of insightful, surprising and sometimes funny observations.

The Americana pays due tribute to music with Dylan acknowledging his debt to Robert Johnson, Hank Williams and Woody Guthrie among others. There are digressions on the Civil War, images of presidents speaking from the back of trains and Truman in a stetson. There are reminiscences of drive-ins, school dances and games with guns.

The book is imbued, too, with Dylan's musings on his personal beliefs but these may be aimed to tease rather than inform. His observations sweep over literature, with Dylan having a shaky grasp of Daniel De Foe (sic) and the death of Tolstoy but being wonderfully dismissive of Joyce and insightful on Balzac. For a renowned womaniser, he is gallant on Joan Baez and Suze Rotolo, two of his main squeezes.

He is capable of mischief. He cites Gorgeous George as an influence, the American wrestler now taking an unassailable position as the showman who influenced both the greatest musician of his generation and the greatest sportsman (Muhammad Ali).

It contains incredible sentences. Of the satisfaction on completing a track on Oh Mercy, he exults: ''Barry White wouldn't have done it better.'' And how's this for the unlikely: ''Bobby Vee and me had a lot in common.'' And the trump card: ''At some point in the day, Tiny Tim and I would go in the kitchen and hang out.''

Dylan devotes one sentence to the motorcycle crash that has spawned much legend, doesn't mention his conversion to Christian fundamentalism and does not give the name of his then wife or their children. He has retained some of the privacy that is so important to him. He peers out of this wonderful, flawed, picturesquely rambling account as a shy, taciturn man, fuelled by four-star ambition. This force compels him. ''I needed to play for people and for all time.''

Thus the mythical two-headed beast faces up to separate fates. Robert Zimmerman will tonight pray ''to be a kinder person''. Bob Dylan is demanded by destiny to prepare to play everywhere from Fresno, California, to Oshkosh, Wisconsin, as the Never Ending Tour goes into an American fall.

Chronicles: Volume One, Bob Dylan, Simon and Schuster, (pounds) 16.99