ON THE STRENGTH of this first volume it seems possible to predict that after the second and third, Michael Holroyd will have completed one of the three great literary biographies of the century, the other two being the late Richard Ellmann's lives of James Joyce and Oscar Wilde. It is perhaps not curious that all three should have Irishmen as subjects. Bernard Shaw predicted, in Back to Methuselah, that with the extinction of the Irish race, and also the Jewish, the life of the world would become unendurably dull.