A comprehensive overview of a catastrophic earthquake which occurred at Tangshan in northeastern China in l976. In addition to a presentation of various aspects of the earthquake, including the geological structures of the area, a history of the seismicity, and the various hazards from an engineering viewpoint, the sociological problems are also discussed. The book presents the results of 20 years research by Chinese scientists, in the field of earthquake prediction, and notes the difficulties they are still facing.