Augustus John, who became famous during the Edwardian era for his portraits of gypsies, women and celebrities and for his visionary paintings mistily entitled ""The Blue Pool"" and ""Lyric Fantasy"" and ""The Red Feather,"" is not the sort of artist one would ordinary expect to share the psychological characteristics of the Age of Anxiety. But such indeed was the case. In Michael Holroyd's finely wrought biography, we learn that this strappingly handsome, fiercely intemperate man was nevertheless strangely passive, ""like a dynamo--one that needed someone else to turn the switch before it came to life."" Terribly vain, yet secretly fearful that ""my work is not good enough""; competitive, but addicted to friendships which he always had trouble sustaining; a great womanizer, yet made distraught and eventually empty by every affair; unfaithful to his beloved wives and quarrelsome among his many children, but unable to do without ""family""--these are some of the numerous contradictions that animated Augustus John's life. Certainly one of the charms of Holroyd's biography is that it reads like a 19th-century novel, full of bustling scenes of London and Paris, many intrigues and changing characters, feuds and imperilments, and at the center of the narrative the heart and mind of its gigantic hero, compatriot of anarchists and bohemians, denizen of the art world and high society. But does all this explain the difficult, inconsistent personality? Holroyd seems content with a trite formula: ""To avoid claustrophobia he needed to move from one self to another, to play many parts in succession like a travelling mummer."" Whether true or not, this ""explanation"" was one John himself was partial to--perhaps he doted on it as a defense. When he was well into his forties he could still write: ""I watch myself closely without yet being able to clarify myself. I evade definition and that must mean I have no character."" Perhaps, on the contrary, he always had too much.