91色情片

Great Comets sounds like a remark startled from Superman. In fact it鈥檚 a fine book on these celestial wanderers, in which Robert Burnham describes what they are and how their mysteries have been unravelled in recent times. Plans to intercept them and land probes on them get an airing-and he doesn鈥檛 forget the occult significance of comets in history. Published by Cambridge University Press, 拢12.95, ISBN 0521646006.