No one likes to be categorized or typecast, but when it comes to creating vivid characters on the page, I find the personality system of the Enneagram a life saver.
Twenty-some years ago, when I first began studying this system, not many people knew about it. It had no huge institutes or psychologists tooting it, as it does now. It was Greek and new age, a little odd. My introduction was through Eli Jaxon-Bear, whose book, From Fixation to Freedom, promoted an Eastern approach that appealed to me. Later I discovered the more Western approach used like Myers-Briggs typing and promoted by Don Riso and Russ Hudson in their Enneagram Institute.