Who are the Interview Subjects from On Writing Well and what is their importance?

The author refers to several of his interview subjects as examples on how to perform and perfect interview techniques. The interview is the best research source because it brings humanity into the story, along with facts that could never be discovered otherwise. Interview subjects are people, and when a writer interacts with people, some kind of magic happens. Ideas pop into view. Questions come to mind, one leading to another in ways that could not have been foreseen. The subjects are the next most interesting part of a writer's work, after the writer's personality.