This is an incredibly thoughtful and insightful talk Vice Chancellor Laster gave to a group of Independent Director candidates (or something, didn't really fully grok the context) at Berkeley last year.
It's a great 101 intro level on "what's an independent director on a Board supposed to do" and I think if you consider it in juxtaposition to how some of the directors testifying in cases like the Tesla trial acted, it will make you think!