No one has been a more eloquent spokesperson for a return to the Moon than lunar scientist Paul Spudis, currently on the staff of the Applied Physics Laboratory of the Johns Hopkins University. This book is both a breathless survey of the history of lunar exploration, using both robotic spacecraft and the astronauts of Apollo, as well as an eloquent statement of rationales for renewed involvement with the Moon.



In his first part Spudis concentrates on describing the Moon and what humans know about it. As a geologist he focuses on the landforms of the Moon, systematically working through discussions of the regolith, volcanism, tectonic actions, impacts and the creation of the lunar face. In this context he discusses in some detail the origins of the Moon, a subject of perennial debate in scientific circles. While still contested, Spudis notes that detailed information from the Apollo exploration of the Moon pointed toward an impact theory--which suggests that the Earth collided with a very large object (as big as Mars or more)--and that the Moon formed from the ejected material. This "big whack" theory explained well what was learned about the geology and selenogony of the Moon during the Apollo program. While there are still details to be worked out, the impact theory is now widely accepted. In the end, Spudis believes that only further research will be able to resolve this question.



The heart of "The Once and Future Moon," however, is Spudis's erudite and impassioned plea for a return to the Moon after more than a generation, the manner in which it might be accomplished, and the scientific activities that might take place there. He offers many reasons for undertaking a renewed lunar exploration program. The rationales include everything from scientific exploration of the Moon, essentially completing the task begun by earlier efforts, as well as developing the resources of the Moon for human use, and engaging in other lunar activities such as astronomy from its surface.



This is a very fine book. Now a decade old, it is time for a new edition of the work, discussing the debate over the possibilities of ice on the lunar poles, and NASA's plans for returning to our nearest neighbor in the solar system. I hope Spudis will undertake this revision in the near term. Until then, I highly recommend this work as an outstanding explanation of the Moon and its place in the human existence.