Non Fiction, Where Do We Come Into This?

Fiction authors should keep a log of what inspired them in their work. It gives the reader such a vast or knowledge of who you are as a writer, and that also just brings in so much good things. As a reader, i want an author's note. I get upset if there isn't one because i wi do to yet i want and i want the book lessond. And this is with fiction, let alone nom fiction.