J. J. M. (Jan Jakob Maria) de Groot, Ph.D., (1854-1921) was a Dutch Sinologist and historian of religion. In this scholarly book published in 1910, he details the history, rituals, and beliefs of the major traditional religions of China: universal animism, polydemonism, specters, ancestral worship, Confucianism, Taoism, and Buddhism. He thought that one spiritual essence could be detected beneath a great variety of religious, philosophical, and even political expressions in China, and his lifework was the discovery and exposition of that essence.