Preface

On Friday 24th May 2013, William T. Powers, the founder of perceptual control theory (PCT), sadly passed away. This book is dedicated to him. I owe him a debt of gratitude. Without his scientific discoveries - my work, my world, and my life, would not make quite as much sense as they do today. Many of my colleagues have had a similar loss. And because Bill continued to be so generous with his time, patient in the face of persistent questions, and crystal clear in his reasoning, the loss was that much greater for all of us. There will no doubt be a story of Bill Powers' incredible life as an engineer, inventor, scientist, mentor, friend, father, brother, and son, but this book is not that book. This is the book that he wanted written by the many people with whom he had shared his vision. Each of them had gone on to share, test, or use his ideas in very different ways, in diverse academic fields, all with Bill's support and of course, feedback. I must particularly thank Alice Powers McElhone, Bill's sister, who through her business, Benchmark Publications, ensured the continued publication of Behavior: The Control of Perception, Bill's first book, as well as the publication of his subsequent works, Making Sense of Behavior and Living Control Systems I, II, and III. From 2013 to 2018, Alice nearly brought the publication of this final book in the Living Control Systems series to completion. We are extremely grateful to Elsevier for taking her good work to the finish line in time for her to witness the fruit of her labors.