The book is concerned with the Ethnic issues of China in the 20th century in general. It includes the conflicts between the foreign aggression and Democratic Revolution, the ethnic issues, the ethnic policies, the development in Xinjiang, Mongols, Tibet and other regions in China during the 20th century. Since China is a country with 56 nationalities, it adopts its own ethnic policy with Chinese character. As the rising of China now in the world with 1.3 billion population and multiple nationalities, the western world may doubt why China can maintain the harmony and high speed economic development in different regions, such as Xinjiang, Inner Mongolia, Tibet, etc. What are the historical causes led to such a multiple-nationality Country? There are unique aspects to this book. One is the detailed analysis on the historical background and reasons for such a multiple-nationality Country; the other is the vivid description of the ethnic policy in China in different minority nations and the interpretation of the issues and solutions for some special regions which the ethnic researchers studied. This book is a comprehensive study on the ethnic issues in China in three dimensions, from the chronological aspect, the policy making aspect, and the inner and international impact on Chinese ethnic issues. If the reader wants to know China, a multi-nationality Country's development, these factors cannot be ignored.