Don't take my word for it (not that you would)
When we return humans to the lunar surface in the next decade, we undoubtedly will build on the science of Apollo, seeking to understand the formation of the Moon and the early history of the solar system. But, perhaps more importantly, we will use the Moon as a test bed for the new technologies that will allow us to venture farther. The Moon is far closer to home than Mars, and it’s best that we thoroughly understand the requirements of human interplanetary travel before we set out on those perilous journeys.
James Lovell
http://www.space.com/news/commentary_lovell_040201.html