Heavenly Clockwork: The Great Astronomical Clocks of Medieval China. By Joseph Needham, Wang Ling and Derek J. de Solla Price. Second edition with supplement by John H. Combridge; Cambridge University Press, Cambridge, 1986. Pp. 320.The Hall of Heavenly Records: Korean Astronomical Instruments and Clocks 1380–1780. By Joseph Needham, Lu Gwei-Djen, John H. Combridge and John S. Major. Cambridge University Press: Cambridge, 1986. Pp. 228.