These documents are related to a revision of 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 SCC, Volume 4, Part 2, hence its inclusion amongst the 'Science and Civilisation in China' research files.