Biographers, in the course of their business, experience many hazards. There is the danger of ascribing to history a soul, a conscious will to a nation. Individuals -- let alone nations-have not a steady will. Rather, they proceed by plunges, one day loyal to their friends, the next day treacherous even to themselves. The biographer must not let herself be tempted into drawing a straight line that leads to some neat historical or moralistic pole.

There is the temptation to slip into antiquarianism, a listing of genealogies, costumes, furnishments -- the sterile part of history. Twenty years ago, when I was writing about Tchaikovsky, my Russian collaborator used to tell me, "We must beware of the samovars and the wolves." With Sir Edward Coke it was the fluted ruffs, the silver armor, the Spanish galleons. Bad theater can obscure the best of plots.

Dr. Johnson said that a historian will turn over an entire library for the sake of one book. Here is a real occupational hazard: the biographer may be crippled by the fear that she is making the mere work of compilation. To sit reading in a room surrounded by ten thousand volumes, shelved and looking down, can make an author truly queasy. "How," asks a seventeenth-century biographer, "how shall I defend myself, that I thrust my labours into the world? What warrant can I plead, that I build a new Cottage upon the Waste?"