Yes, one uses what one knows, but autobiography means something else. I should never be able to write a real autobiography; I always end by falsifying and fictionalizing—I’m a liar, in fact. That means I’m a novelist, after all. I write about what I know.
Our ideals, laws and customs should be based on the proposition that each generation in turn becomes the custodian rather than the absolute owner of our resources - and each generation has the obligation to pass this inheritance on in the future.
There are many reasons for keeping a diary: to make a note of facts that one considers important; to open one's heart, to give vent to one's feelings, to make confessions; from the instinct of economy which sometimes encourages a writer to make good use of even the smallest crumbs of his life, so that he may have one more book to publish; or again from vanity and self- satisfaction.