Heinlein's forth and final Hugo, The Moon is a Harsh Mistress is a thriller of revolution and interplanetary war, a tale of an unlikely friendship between man and machine, and a credible study of the evolution of human culture.

Taking these themes in roughly reverse order: in the year 2075 the moon is home to 3 million human beings, the descendants of convicts and exiles continually sent up by an overpopulated Earth. The world-building is top-notch, revealed through the narrator's clipped Loonie speech patterns and creole of English and Russian, and millions of those tiny details Heinlein is rightfully famous for. Heinlein has spent a lot of time thinking about life in low-gravity, and that work pays off here in effortless descriptions on lunar life. Most key is the gender ratio: most convicts are male, and even now there are two men for every woman on the moon. Plural marriages are common, from simple triads to clans and lines and more complex arrangement. The deadly lunar environment and lack of women have created an elaborate code that gives women all the power in every situation. A man that so much as touches a woman without her consent is likely to be thrown out the nearest airlock. Where many scifi cultures feel like they're thrown together from whatever the author found interesting, without much sense of history.

Second is the friendship between our narrator Manuel O'Kelly Davis, and the real hero Mycroft, a HOLMES type supercomputer operated by the Lunar authority. Mycroft (call him Mike) achieves self-awareness shortly before the start of the books, probably from being linked into every system on Luna. With Manny, Luna's best computer tech as his first friend, Mike goes from brilliant child to being of many personalities and a great deal of complexity. Mike is the ace-in-the-hole for the Revolution, handling communications, strategic analysis, and the big guns.

Oh yes, the Revolution. Even though Luna is a prison, it's almost irrelevant because there's nowhere to escape to, aside from the airless surface. The Lunar Authority controls all the ships, and lunar people adapted to 1/6th G have a great deal of trouble on Earth. The Lunar Authority buys grain for too little and charges too much for imports, but most Loonies barely notice. Except that if grain shipments aren't stopped, Luna will have food riots in seven years, cannibalism in eight, and nobody seems to notice or care about the grim future. It's up to Manny, and his fellow conspirators in Mike, Lunar patriot Wyoming Knot (practically the only Lunar patriot), and exiled professional revolutionary Professor Bernard de la Paz to lead a revolution and save the Moon! There's great stuff on conspiracy, on cellular organizations, and how to use propaganda to turn an apathetic population against a more or less hostile authoritarian occupying force. The climax of the book, with the Loonies 'throwing rocks' as a strategic demonstration of force, is some of the most exciting stuff in fiction.

But I mentioned that this is the last Heinlein-worth-reading, and there are two reasons. Heinlein always enjoys playing around with political systems and ideologies, and this is where he makes a final judgment. The only truly fair ideology is de la Paz's "rational anarchism": you do whatever you want up till the point where it affects me, and I'll do as little as possible that affects you. Everything else is just the twittering of yammerheads and petty injustices of bush-league authoritarians. Pure selfishness cloaked in high-minded ideals and appeals to common sense, in other words, and one that ignores everything we know about what it takes to live with strangers. It's in some ways more opposed to democracy than the fascism of Starship Troopers, which starts from the basic premise that the people are sovereign. I don't mind staunch libertarianism in fiction; I do mind that Heinlein gives up on thinking about politics at this point in favor of the individual uber alles. Second strike against late Heinlein is the weird sex stuff (e.g. time travelling incest), and while it may make sense in the context of Lunar culture, I have no interest in hearing about how weddable 14-year old girls are. I hate to end on a low note, because the book is great, but the signposts for 'go no further are all there.'

On an interesting historical aside, Luna wins its independence in a graduated campaign of strategic bombing against primarily symbolic targets to indicate that they can hit cities at will. At the same time as The Moon is a Harsh Mistress was being published, America was engaged in a much less successful campaign of 'communication bombing' against North Vietnam in Operation Rolling Thunder.