The core of the book are six papers by Dr. Richard S. Marken which have been published in peer reviewed journals over the past decade explaining why Perceptual Control Theory (PCT) offers the most promising approach to understanding behavior to date, and lays the foundation for a true science of psychology. A friend and advocate of the late William T. Powers, originator of PCT, Marken's assessment of where this new science will take us in the next fifty years is compelling as it is exciting.