Abstract:The rapid accumulation of massive amounts of data in biology information technology and various branches of social science in recent years has prompted the development of novel quantitative methods. Statistical mechanics, as a mathematical theory that connects microscopic and macroscopic descriptions of systems with many degrees of freedom, can play an important role in this process. A short review of recent progress in the application of statistical physics methods to a broad range of complex phenomena is presented here. From the examples discussed one may obtain a glimpse of the power of the statistical mechanical approach in capturing the system dynamics at different levels of representation and on many different time scales. With the help of simplified models and approximate treatments, the key variables and their interdependencies can be elucidated. Further theoretical considerations and comparative studies may lead to the discovery of unifying principles. The opportunities and challenges in a closer integration of statistical physics and complex systems science are briefly discussed.