The HBDI "circle" contains four concentric rings. The two outermost indicate a preference for the quadrant. The third indicates use of the quadrant and the fourth (innermost), avoidance.
Hermann labels the upper left quadrant "A." He describes people with preferences in this quadrant as "logical, analytical, mathmatical, technical, and scientific." The lower left, "B" quadrant describes people who are "controlled, conservative, organizational, and administrative." The upper right, "D" quadrant is where creativity comes into the picture. People with preferences in this quadrant are "imaginative, synthesizers, artistic, and think non-linearly." The lower right quadrant, "C" desbribes those who are "social, emotional, spiritual, and talkative."
Hermann contends that the goal is to become "whole-brained" and able to use the characteristics of each of the four quadrants.
His book is in a landscape format and is chock full of interesting and entertaining illustrations. Personally, I find his "type" theory to be more descriptive and useful than the more widely-used and touted Myers-Briggs. I recommend this book without reservation.
George Mason University
Fairfax, VA 22031