"The ability to predict has always been, and remains, an important aim of science. In traditional China, astronomers devised methods of divination that were not only applied to natural events such as weather forecasting, but also to mundane human affairs. The three most sophisticated devices were shrouded in clouds of secrecy. During the eleventh century and for hundreds of years thereafter, candidates were examined on their knowledge of these devices behind the closed doors of the Chinese Astronomical Bureau." "Known by little other than their names, this is the first book in any language that attempts to make an academic study of the three methods, known as the sanshi (three cosmic boards), which turned out to have a profound influence on Chinese society."--BOOK JACKET.