Theoretical Apparatus in Biography

There is no such thing as a definitive biography of anybody, and that's an important fact about biography. But surely there is some theoretical apparatus at work because when you write a biography, you don't include everything that you find. Litten Straitschie said that what distinguishes a great biographer from a mediocre one was what he called a point of view. What it presents is not as it were all the facts, of course. A biography shapes, it shifts, it selects, and therefore there's an art.