Facts are as complex as atoms and sometimes it seems almost as dangerous. It is a fact that our biographical subjects tell lies, a fact that their lives are guided by fantasies - often fantasies of the lives which, because of this decision or that decision, they haven't lived, but which still shadow their actual living and enter their dreams as clues and signposts to a parallel existence. And we, their biographers, have our fantasies too which, like magic carpets, can carry us through time and give our readers sympathetic access to people they have never met, people whose temperaments and opinions may well be utterly different from theirs, strangers they may get to understand and with whom they may even feel an intimacy.

Facts are as complex as atoms and sometimes it seems almost as dangerous. It is a fact that our biographical subjects tell lies, a fact that their lives are guided by fantasies - often fantasies of the lives which, because of this decision or that decision, they haven't lived, but which still shadow their actual living and enter their dreams as clues and signposts to a parallel existence. And we, their biographers, have our fantasies too which, like magic carpets, can carry us through time and give our readers sympathetic access to people they have never met, people whose temperaments and opinions may well be utterly different from theirs, strangers they may get to understand and with whom they may even feel an intimacy.

These days, biographers are more than mere information gatherers. Information is merely one of the building blocks of modern biography and autobiography, a raw material that we try to convert into knowledge - something experienced, that is, through the imagination.

Early in the 20th century biography was woken from its slumbers by Lord Strachey, that enfant terrible of our genre, and then, at the end of the 1950s, it grew to full maturity and sophistication with the publication of Richard Ellmann's masterpiece, his life of James Joyce. Contemporary biographers have been working in an extraordinarily stimulating climate - a golden age some critics have called it, a second golden age after that of Johnson and Boswell.

"No species of writing," Johnson wrote, "can more certainly enchain the heart by irresistible interest... We are all prompted by the same motives, all deceived by the same fallacies, all animated by hope, obstructed by danger, and seduced by pleasure." That is surely as true now as it was then.