Thanks for the book suggestions. I didn't know about the Moon Morphology book. I hope it is available for around $40. Most used bookstores have it for $100 to $250.

I have Harland's Exploring the Moon, but haven't read it yet. His Jupiter Odyssey covered the geology of the Jovian moons very thoroughly.

I have and have read and enjoyed To a Rocky Moon and The Once and Future Moon. I also have Thomas Mutch's excellent Geology of the Moon, which I think you can find pretty cheap.

Other lunar geology books worth mentioning are the Lunar Sourcebook and the Preliminary Science Reports, which are now online at ALSJ. I bought the Apollo 15 and 17 ones back in the early 80s for around $8 a piece. I want to kick myself for not ordering them for all the missions.