Mark Twain was an American writer, humorist, and lecturer, best known for The Adventures of Tom Sawyer and Adventures of Huckleberry Finn, often called the "father of American literature." Twain's great achievements in society, culture, and literature shine brilliantly in human civilization, bringing joy to humanity. However, just as he reached great heights, deep valleys of misfortune cast dark shadows over his life. As we reflect on the hardships endured by Twain and his family, we cannot help but feel profound sorrow and heartbreak. The immense trials that Twain and his family faced continue to repeat themselves in our world today. Modern science and medicine have not been able to explain or resolve the deep-rooted misfortunes that plagued Train and his family, because they fail to grasp the fundamental principles that govern human life and fate. While modern science and medicine evolve based on secondary variables, the primary variables-those that truly dictate human well-being-remain unaccounted for. Unless these higher-order principles are understood and incorporated, the tragedies experienced by Twain and his family will continue to repeat endlessly. Could Twain and his family have avoided their misfortunes? The outcome of an equation is determined by the variables within it. If we can correctly identify the variables that led to their suffering and alter them, the problem can be solved. The fundamental cause of Twain's and his family's misfortunes can be clearly identified, and a solution exists. That is precisely what this book aims to present. At the heart of this understanding lies Yin & Yang and the Five Life Forces, the foundational principles of Eastern philosophy. In the realm of the mind and spirit, Yin & Yang and the Five Life Forces have often been seen as abstract and elusive concepts, difficult to believe in or empirically validate. However, these once-vague principles have been structured into a tangible medical framework through Eight-Constitution Medicine. From the perspective of Eight-Constitution Medicine, which is based on Yin & Yang and the Five Life Forces, we find answers to these persistent human struggles. This perspective represents a paradigm shift as revolutionary as the transition from the geocentric model to the heliocentric model-a true Copernican revolution in thought. It is my hope that this book, Mark Twain Syndrome, will serve as a catalyst for a profound transformation in human civilization.