Some have suggested that this is one of Heinlein's most political books, and while it this is only the forth that I have read so far, I am probably not that inclined to agree. While it was much better than Podkayne of Mars, it was pretty much on par with Stranger in a Strange Land (the other one I read was Starship Troopers). In a way, one could say that this novel is an anatomy of a revolution, in the same what that Stranger in a Strange Land is an anatomy of a religious cult (and while I could say that Starship Troopers is an anatomy of an army, the army in that book seems to be of a different sort than what we know of armies today).
The book is set about 100 years in the future at the time of writing, which at the time was in the middle of the space race. Basically the novel appeared almost half way between Kennedy proclaiming that by the end of the decade they would have put a man on the moon, and Nixon actually doing it, and this was played out in the background of Russia attempting to do the same thing. However, despite a number of voyages during the 70s, all of the sudden the idea of visiting the moon suddenly dropped off, and nobody has been back since.
Anyway, at the time of writing, people were still looking forward to the possibilities of what might come of the space race, and one of them was a full fledged colony on the moon. However, it appears that in Heinlein's future, the colonisation of space had ended with the moon. Luna has become a penal colony, and it was sustained by the enormous amounts of ice found there (which solves the water problem) and has been turned into a farming community that exports grain to Earth (which to an extent solves the oxygen problem as well). It is also suggested that much of the food is grown hydroponically.
However, life on the moon is not pleasant. In a way it reflects the world of the late 18th and early 19th century, where the Great Powers of Europe would establish penal colonies in far away locations (such as Australia and Siberia) and if one was sent there there generally was no hope of ever returning. This is the case with Luna, because it is too expensive to send people there and back, and while there is some two-way traffic, it is not common, and in fact the colony is run from Earth by an organisation known as the Lunar Authority, though there is a Warden who lives on the moon.
Some have said that this is a handbook on revolution, but I do not think that that is the case. Rather Heinlein is telling a sort of future history. The story is written as a memoir of by one of the leaders of the revolution, though it is interesting to note that everything is meticulously planned, and the person writing the memoir, a techie named Manuel, is little more than a puppet. It is also interesting that the head of the revolution is a computer named Mike who is convinced to participate because he is interested in learning about humour, but also because the only person that he considers a friend is Manuel. While Mike was built by the authority, it is his programmer than he comes to trust, which makes us wonder whether it is the owner, or the maintainer, that truly controls a computer system.
Heinlein says a lot of really interesting things in this book. Sort of short one liners that make you think quite deeply about what is going on. At the beginning of the book he talks about Mike's processor speed, and in fact this is raised a number of times during the story. Remember, this was written in 1965 when computers still pretty much filled a room (and were much less powerful that the computer currently sitting on my lap on which I am writing this). What caught me though, and it is something that I have read elsewhere, is that the faster the computer processes information, the slower time appears to the computer. It made me think that if I could actually speed up my brain's processing ability, I could actually slow time down, at least to my perception. Obviously, the problem with that is that if my brain was operating a four times the speed that it currently is, that means that I would simply not be able to communicate with anybody around me (because I would be talking at four times the speed that I am currently speaking). However, it would mean that my train trips into the city, and my plane flights would be four times as long, which means I would be able to get through much more reading than I currently do. However, watching movies would be an absolute pain, unless I could effectively speed them up as well, but unfortunately it generally does not work that way.
Another thing that I found intriguing was when the professor (the real brains behind the whole revolution) outlined how a constitution should be drafted, and that is that it should be full of things that a government cannot do. Many constitutions are like that, though others simply outline how the government bodies are constituted and how laws are passed and interpreted. It is interesting that when Napoleon went storming across Europe, he would set up constitutions in countries that he conquered modelled on the new French Constitution, though I suspect that the states that the Americans are 'helping' to establish, are begin directed through their own imperialist agenda. The Australian constitution is set up to give the government restrictive powers, in that there are a set of powers that it has and can use, and only use. I guess that reflects John Locke's idea that nothing is beyond the power of a parliament. I suspect that Heinlein was thinking of that idea when he wrote the passage about filling a constitution up with restrictions on what a government can do.
Anyway, all of this is idealistic, and Heinlein knows this as well, because despite the revolution that runs perfectly (but he does give good reasons behind that as well), human nature is human nature, and he knows that. We see this when the Earth is being bombarded from orbit. Despite warnings that the people of Earth should stay away from certain places, and despite the attempts to hit places that people would not be, people instead flock to those locations, believing that the Loonies (inhabitants of Luna) are bluffing. Mind you, in the end, the whole idea of the revolution is based entirely on bluff and counterbluff, and who is willing to call which bluff. The problem with calling a bluff though, is that you can never know if your opponent is bluffing until you call their bluff, and by then it is too late.
One final thing, I really did like how Heinlein structured the language of the Loonies. It seems a bit odd at first, but you soon get used to it. Basically it is full of redundancies, namely anything that is not needed is tossed out. He also indicates that it has borrowed from other languages, sort of a result of the mixtures of cultures that have appeared on the moon, though he restricts this to da (yes in Russian) and Nyat (no in Russian), and a small smattering of German sounding words that Google Translate doesn't seem to recognise. I guess he was very restricted in that way since he was writing to an English audience, and too many borrowings from too many languages would have made the book unreadable.