In this book Dr. Xu Ze wrote down how to prevent cancer and try to stop cancer at the source and strive to eliminate security risks of cancer in the bud in detail. All of his wisdom comes from his hard work and years practices. Cancer prevention is the same important as the cancer treatment. Cancer prevention and treatment should be conducted at the same time and at the same level. It is very important for us to be aware of the cancer prevention. Once again the tears are full of both of my eyes, it is hard work all of day and night for all of our projects. The journey of getting all of these results is not always smooth and Science is endless. With the science and technology development, cancer is gradually understood in depth. Many research data proved that more than 90% of cancer can be prevented. In this book, Dr. Xu Ze wrote down the plans of how to prevent cancer occurrence before cancer happen and how to prevent cancer from the daily life in detail. In China, there are many of the wisdom words such as: the topmost doctor manages the country; the middle level doctor prevents the disease or treats the diseases before it happens; the lowest doctor treats the diseases. Prevention of cancer is very important. The essence is to implement and carry out the health work policy of "cancer prevention and anti-cancer" and "prevention-oriented". Our medical predecessors and the world's medical sages put forward "cancer prevention and anti-cancer" and "prevention-oriented". This policy is very correct. Let work hard together to conquer cancer and do the good things for our human being.