This book presents a gradual path toward educating readers in understanding how Control Systems truly operate and in recognizing, simulating and improving them in all fields of activity. Starting from the hypothesis that knowledge of Control Systems is not only a technical fact but also represents a discipline that is, A discipline is a developmental path for acquiring certain skills or competencies. () To practice a discipline is to be a lifelong learner. You never arrive; you spend your life mastering disciplines. (Senge, 2006, p. 10) Piero Mella has set the objective of making Control Systems a topic that is, in a certain sense, simple and attractive by turning to the effective symbolism typical of Systems Thinking models and avoiding too technical and formal a treatment of the subject. Thus readers should know that this is not an engineering, physics, biology or economics text, nor a mathematics one either. Technical or mathematical tools are not necessary to construct Control Systems; instead the book adopts a highly simple and universal logic behind the notion itself of control process and the simple and universal action of the Control Systems that produce this process. The Magic Ring: Systems Thinking Approach to Control Systems is divided into 10 chapters. Chapter 1 seeks to review the basic language of Systems Thinking and the models it allows us to create, while Chapter 2 introduces the control process, presenting the theoretical structure of four simple Control Systems we all can observe and manage. In Chapter 3 a general typology of Control Systems is proposed with examples taken from observations of reality. The view of Control Systems is broadened in Chapter 4 by introducing two important generalizations: 1. multi lever Control Systems, with levers that are independent or dependent of each other; 2. multi-objective systems, with independent or interdependent objectives. Chapter 5 outlines the guidelines for recognizing, observing or designing Control Systems and presents the problems that arise regarding their logical realization, introducing the fundamental distinction between symptomatic and structural control. Chapters 6-9 undertake a mental journey through various environments, increasingly broader in scope, suggesting to the reader how to recognize therein Control Systems that, by their ubiquitous presence, make the world possible in all its manifestations. Finally Chapter 10 covers ideas about a Discipline of Control Systems and the human aspects of control.