ABSTRACT
Any discussion of the Moon is often linked with that of the terrestrial planets. It is a rocky body in the terrestrial region, and its general appearance is not very different from that of Mercury. It has been studied from the Earth with telescopes for about 400 years, and it is the only body outside the Earth that has been visited by man. For this reason, our knowledge of it is better than that of any other solar-system body, except the Earth.
