Presumably, in order for there to be a biography of someone, someone else must decide that they're worth writing a biography about.
How is this determination made? I assume that publishers are interested mostly in selecting biographies that are likely to sell well. Some prominent public figures (autobiographies by ex-Presidents, for example, typically make the bestseller list) are obvious candidates, but what about "lesser-known" individuals?
Is there a particular standard for how notable or "interesting" someone had to be?
It seems a bit arbitrary at times why certain people have biographies written about them and other people don't. For every prominent public figure who has a biography, you could probably find dozens of equally prominent people who don't.
What's the usual process for an author or publisher deciding to write (or publish) a biography on someone? What kinds of things might a publisher consider? What reasons might they give for publishing a biography on a particular individual, and what reasons might they give for not publishing a biography on a different individual?