Depending on their national level of income, development and modernization, all countries in the world can be generally categorized as either advanced or developing. Studies on why advanced countries continue to develop, how they maintain their level of development, and how developing countries enter into the advanced club fall into the field of modernization science, which is an emerging interdisciplinary science. This monograph, the first English book available on modernization science, interprets its concepts, methodologies, general theories, first and second modernization, six level-specific, six field-specific and three sector-specific modernizations, modernization policy and evaluation, and the principles and methods of national development since the 18th century. It provides clear, systematic, up-to-date information on this new discipline with more than 173 figures and 265 tables, and covers 131 countries and 97% of the global population. A comprehensive outlook on world modernization is presented from a Chinese perspective.