These documents are related to the monograph 'Heavenly Clockwork: The Great Astronomical Clocks of Medieval China - A Missing Link in Horological History' written by Joseph Needham, Wang Ling and Derek J. Price. It was published in 1960 by Cambridge University Press in Association with the Antiquarian Horology Society. Material from this publication was also used in 'Science and Civilisation in China, Volume 4, Part 2', hence the existence of further material on horology in SCC2/104-109.