Planetary Geology
Guest et al
1979

"Our most complete history of another planet other than Earth is that of the Moon."

Planetary Science: A Lunar Perspective
Stuart R. Taylor
1982

"The Moon remains the only body which we have visited and sampled with a proper understanding about the revelation of the samples to the overall evolution of the planet. The Moon, as revealed from those studies, is sufficiently different from the Earth, both to render terrestrial analogies hazardous, and to provide another example of planetary differentiation processes. The tendency to regard Earth as a norm, and terrestrial geochemical processes as a model for those on other planets, has not survived the encounter with the lunar data. Many details, such as the contrasting behavior of chromium on the two planets..."

The Once and Future Moon
Paul D. Spudis
1996

"This object [the Moon] is a complex planetary body with its own history of geological evolution..."

on the Moon
Patrick Moore
2001

"Officially the Moon is not ranked as a planet, and is relegated to the status of a mere junior attendant to Earth. I am not at all sure that this view is justified...Admittedly there are four planetary satellites which are larger than the Moon - three in Jupiter's family and one in Saturn's - but these move around giant planets, and are very small and lightweight compared with their primaries. the Moon has 1/81 the mass of the Earth. The mass ratio between Jupiter and its largest satellite, Ganymede is 17,700 to 1; between Saturn and Titan it is 4,150 to 1. Apart from Earth, there is no small planet with a large satellite (I exclude the Pluto/Charon pair, which is in a different category altogether). It may or may not be significant that the ratio between the Earth and the Moon is not wildly different from that between Venus and Mercury. [7% vs 1.2%]"

New Frontiers in the Solar System: An Integrated Exploration Strategy
Solar System Exploration Survey
National Research Council Space Studies Board
July 9, 2002

"South Pole-Aitken Basin Sample Return (SPA-SR)
SPA-SR will return samples from the Moon in order to constrain the early impact history of the inner solar system and to comprehend the nature of the Moon's upper mantle. The South Pole-Aitken Basin, the largest impact structure known in the solar system, penetrates through the lunar crust. It is stratigraphically the oldest and deepest impact feature preserved on the Moon. The SPA-SR will help determine the nature of the differentiation of terrestrial planets and provide insight into the very early history of the Earth-Moon system. SPA-SR will also enable the development of sample acquisition, handling and return technologies to be applied on other future missions."

Sorry guys, but sounds like the Moon is considered a valid source of what could be termed by a reasonable person as comparative planetology. I've certainly got to give the words of Sir Patrick Moore a certain amount of weight, he's quite well respected in the astronomical field.

The National Research Council report was quite an interesting read. There were only five projects that cut across three of the four "Crosscutting Themes and Key Questions": Jupiter Polar Orbiter w/Probes, Comet Surface Sample Return, Venus In-Situ Explorer, SPA-SR, and Kuiper Belt-Pluto Explorer. We all know which one got all of the attention.

I'm not sure why evryone seems to be so quick to dismiss the science on, of and from the Moon. There's good scientific stuff there, well worthy of our attention and respect.

Ken