In ancient China, the Origin of the universe was called Dao. Dao theory is the ultimate theory established by ancient Chinese thinkers based on the Origin of the universe. It is used to explain all basic phenomena in the universe, to guide people's thoughts and behaviors, and to establish a just and perfect society. Consciousness, soul and life are the most important phenomena in the universe and also the most difficult to explain. Using Dao theory, we can explain and study human soul, consciousness, emotions, feelings and life. Although consciousness, soul and life have complex and difficult sides, they also have simple and easy-to-understand sides. The basic principles that form consciousness, soul, and life are simple; Even if you only have a middle school or even elementary school education, you can understand it as long as you put in the effort. Dao theory is composed of Yin-yang theory and Dao Morality Scripture (Tao Te Ching). This book is divided into three parts: the first part briefly introduces the Dao theory founded by ancient Chinese thinkers; introduces the yin-yang theory, using the Yin-yang theory to explain consciousness, emotions and feelings; introduces the three major worlds that make up the universe: the Dao world, the Soul world and Human world. The second part translates and interprets the Dao Morality Scripture. The third part introduces the application of Dao theory in contemporary human society. In Dao Morality Scripture, Lao Zi advocates "zero-action", "keeping the middle", "pure-quiet", "fraternity" and "contentment". When you understand consciousness, you will know that what Lao Zi said is correct. To correctly understand the Dao Morality Scripture (Tao Te Ching), it is recommended that you first understand the basic principles of consciousness. The universe was created by Dao, and the theories established based on Dao must be able to explain all basic phenomena of the universe. This book proves that Dao is the most perfect spiritual body in the universe; therefore, the theory established based on Dao will definitely be able to guide mankind to establish a perfect world. At present, problems faced in the fields of consciousness, life science, physics and other fields need to be solved by Dao theory; various problems faced by human society also need to be solved by Dao theory. Dao theory is the most basic theory that everyone should understand: If you want to understand the Origin of universe and understand why the universe is produced from emptiness, I recommend the Dao Theory to you. If you want to understand consciousness, soul and life, I recommend the Dao Theory to you. If you want to know what the correct beliefs and codes of conduct are, I recommend the Dao Theory to you. If you are a politician or public official and want to find the correct theory of establishing a country, I recommend the Dao Theory to you. If you are a student or researcher of philosophy, social science, natural science or religion, I recommend the Dao Theory to you. …… This book is available in two editions: the popular edition and the physical edition. The popular edition contains spiritual physics, omits general physics, and reduces 178 pages. The popular edition is suitable for readers majoring in liberal arts, and readers with middle school and primary school education. The cover of the popular edition is yellow, and the cover of the physics edition is blue. This e-book is a physical edition. There are many diagrams and formulas in the book, so it is a PDF e-book. It is more suitable for readers with 9 to 10-inch screens.