Edit. Harvard University Press, 1981 Cambridge. 4ºm (23,5x16cm). 284 págs. Rústica ilustrada. Cubierta deslucida. «Whipple is one of a rare species, a thoughtful scholar amongst the rush and glitter of the recent explosive activity in the planetary sciences… A delightful, well-writen, non-technical account of planetary research.» -American Scientist