To quote from amazon.com, this is a story of "revolution on the moon in 2076, where "Loonies" are kept poor and oppressed by an Earth-based Authority that turns huge profits at their expense. A small band of dissidents, including a one-armed computer jock, a radical young woman, a past-his-prime academic and a nearly omnipotent computer named Mike, ignite the fires of revolution despite the near certainty of failure and death. "
Ideas: interesting. Characters that spout them: rather flat.
I liked the story, though I wasn't too impressed by characters. The characters are believable, but perhaps too simple for my taste. The radical young woman, Wyoming, and the Professor are more or less cardboard cutouts. The only reason for Wyoming's existence seems to be to make rash, immature statements so as to give the Professor a chance to say: "no, dear lady, we can't do that, here's why..." and then expound on one of his theories. But I didn't mind because his theories were quite interesting. It was worth reading the book just for them. It was interesting to see how Luna's revolutionaries put those theories into practice. I was intrigued to find out what kind of leverage the Loonies will find in their negotiation with Earth. Luna's economically and technologically disadvantaged position should have made it near impossible, and yet they found it. That was interesting. Still the story would have pulled me along much better if there was some character development, some interpersonal drama.
Exquisite worldbuilding, based on shaky premises
To me the most interesting aspect of this book was Heinlein's portrayal of Lunar society. The community of Luna started out as a penal colony. At the time period the story is set in, Earth has been shipping its criminals to the Moon for many decades. Over several generations the Lunar population came to consist mostly of descendants of the original "settlers", with an influx of new convicts constantly trickling in. Since most convicts were men, the initial demographics of the Lunar population suffered from a huge gender imbalance; even after all those decades men still outnumbered women 2:1. This society has no laws; rules of behavior are enforced by nothing more than people's mutual consent.
The book is sprinkled through with little incidents that help us get a feel for Lunar reality. For example, there is the episode where the protagonist, Manuel, is asked to be a judge in a dispute between a bunch of local boys and a visitor from Earth. I found it very exotic, since it is unimaginable to us that a dispute involving possible capital punishment might be left for any random citizen to arbitrate. While those episodes had an authentic feel (possibly because of Lunar slang used heavily throughout the book), they did not convince me a society could function without laws. Heinlein's explanations of how such a society works are a bit too simplistic. For example, he says: who needs laws to enforce contracts, when a person's reputation should be sufficient? I think while fear of loss of reputation might work in very small societies, in bigger societies it is impossible for everyone to have accurate knowledge of everyone else's reputation. As far as allowing random citizens to act as judges and make arbitrary rulings not based in any laws, there is so much room for abuse of power. I think what would have happened in a completely anarchist society (especially one that was made up primarily of criminals), is that this society would have devolved into a dictatorship of gangs. I also don't believe women would have enjoyed a special status because they were a minority. I don't think men would leave all the freedom of choice to women and quietly abide by women's decisions. Most likely they would put women in burqas, lock them up, and sell and trade them like chattel.
So, Heinlein's picture of an anarchist paradise seems quite unrealistic to me. Another dubious premise on which the book is based is that a sentient computer (Mike) would remain in service of people who think millions of times slower than he. Wouldn't he find human affairs to be intolerably tedious? Wouldn't such a computer pursue goals of its own, which may differ greatly from humans' goals?
Overall, "The Moon is a Harsh Mistress" is an interesting speculation about societies and revolutions, though I didn't find it convincing. But it's easy to sympathize with a story of a small, ostensibly powerless entity like Luna breaking free from an immensurably more powerful authority. To pull it off required no small amount of cleverness. All in all a worth read.
(As an aside, I really like the main character's manner of speech in which he often drops pronouns, articles and auxiliary verbs. I loved the Lunar slang too, it's quite charming. It gave the harsh setting an oddly cozy feel.)