For a biographer who cannot speak to her subject—because she is no longer alive or unwilling to be interviewed—there is nothing more revealing than this person's journals. If, that is, she kept a journal, if it still exists, if it can be located, and if it can be read. (Often, such private musings are labeled as "restricted" in archives for a certain period of years.)
In the absence of a journal, letters to relatives, friends, enemies, and colleagues (often, overlapping categories) are the most intimate traces of a person. Letters are written for many reasons—to praise, to thank, to argue, to demand, to cajol, to ruminate . . . and, most tellingly, to pour out one's heart at a time of trouble.
Granted, the letter writer may be bending the truth to appeal to the recipient of the letter. But that possibility can be revelatory in itself: Why is this person being "handled" in this way? What is the writer hoping to gain?
Something that has puzzled me in certain reviews of my most recent book is that the dozens of excerpts from my subject's letters were somehow not considered to paint a true portrait. Many of these letters were written when Elizabeth Hardwick was feeling most vulnerable, when she couldn't decide whether to leave her brilliant but mentally ill and unfaithful husband. Others were written earlier, to describe her fractious relationship with her mother and impressions of earlier men in her life, or later, to recount social occasions and other events, and the progress of her writing.
These letters were not necessarily written with the same stylistic brilliance as her published writing. Someone who interviewed me wondered about this. But why would they be? Some of them are the anguished cries of a woman at the end of her tether, as opposed to, say, carefully framed remarks about women in the plays of Ibsen. The reason the letters are so vital to an understanding of Hardwick is that they reveal her quandaries, delights, and deeply personal thoughts at diverse moments of her life.
I should add, for those who haven't read my book, that I never include the entire letter, which would involve what is known as a block quote—a thicket of verbiage that stands apart from the ongoing narrative. Rather, I pluck out the most telling sentences and let them speak for the whole in order to keep the narrative moving at a good pace.
What reviewers wanted, it seems, was more interviews with people who knew my subject, who could report on what she said at a dinner party or while sitting on a literary jury. There are interviews conducted by me in the book, but few are with famous people. The main reason is that these people—notably Robert Silvers, editor of The New York Review of Books—were deceased by the time I began researching the book in 2019. (Some quoted remarks by people no longer living are from interviews conducted by other people during the lifetime of the speaker.)
Interviews, if used well, can be a useful feature of a biography—particularly interviews of the subject herself. Interviews with others can give some idea of how the subject was viewed by friends and colleagues. One type of interview that doesn't interest me, however, is with someone who recounts stories the subject told about her earlier life. Why would I trust such second-hand memories—so often actually poorly remembered or distorted by wishful thinking—when I have the letters (or, in some cases, journal pages) that provide on-the-spot documentation?
Some biographers consider interviews as a sort of numbers game, no matter how relevant or meaningful the quoted remark may have been—and no matter whether the quoted person met the subject for ten minutes or knew him for a lifetime. (One author of a fairly recent literary biography even included in his book a long list of every single person he spoke to. Never mind whether all these folks had anything worthwhile to say.)
I actually chose not to include some remarks uttered by people I felt were being unfair—because they had an ax to grind, or because they were not in a position to judge the situation.
My main point is that no interviews with people who knew a subject can ever hope to rival the intense immediacy of her letters. This is where we can look for the "window on the soul" that I believe all biographers ultimately hope to capture.