Searching for the Meaning of Life emphasizes the basic principle that should be followed when we discuss the meaning of life. We may discuss this principle in religion, psychology, and philosophy; in this book, however, we will start from Tao Philosophy, where Lao-tzu describes the rules of nature as The Principle of Oneness. The state of nature is where we can attain the state of joy. We may thus base our meaning of life on nature. By returning to nature, our life will be free from all anxieties, and return to joy. This is the state of Oneness of all. The goal of religion, psychology, and philosophy is to discover joy. Therefore, we may see how this principle is used to construct the meaning of life, by eliminating anxiety in our lives and by making Now meaningful in our life. We shall discuss this principle in tams of religion, psychotherapy, and philosophy. Ancient religion started to relieve the disturbance of this problem by assume the immortality of the soul to affirm this life with heaven and reincarnation. Some religions will tell us that all evils are caused by our own acts and life is suffering, until you can get eternal peace and joy. The meaning of life is to believe and obey God's will, so that we can be saved. Some other religions teach that we can find a life free from pain. Various denominations have a complete system to allow us to establish a system of meaningful thought. Modern people also use psychotherapy to help find the road to peace and joy. Austrian psychiatrist Sigmund Freud (1856-1939) began looking for the lost meaning of life. This started the traditional treatment of morbid psychology. However, modern humanistic psychology emphasizes the use of psychological therapies to build a healthier personality. Such healthy psychological therapies allow us to actively pursuit of the meaning of life. In philosophy, ancient and modern philosophers alike think that joy is the purpose of life. To pursuit truth is our tool for liberation. Although philosophers are diverse, the most common denominator is to know the truth in the world. Truth will bring meaning to life. When we can live in truth, we will get real joy. What is considered as truth in philosophy is the truth in nature. Lao-tzu and ancient Greek philosophers associate nature with "One," since nature is a whole. In our life, we have to reconstitute the various bits and pieces into a whole, in order to return to nature. We can't create the meaning of life; we have to discover the meaning of life. This does not mean that our life has no meaning. For everyone, life is a real life, not an illusion. As long as we are alive, we must be sure of our own life, and we have to respect the life of others. Life seems to be a game without rules; everyone may design a custom rule. The rules are not the same, but there is a common principle. We shall discuss this common principle in this book. This book will show that, by adhering to the common principle, our custom rules will appear reasonable. Under this principle, each custom rule is of equal significance and the ultimate judge will not be arbitrary, because custom rules and the ultimate judge will reflect the same common principle and will be fair. We then can have a meaningful life and can respect life of others.