But for whatever reason I never ventured further into Heinlein's oeuvre, and am making up for that deficiency now. And this is the big one. Along with SiaSL, this is one of Heinlein's best known, one of the ones that put him in the pantheon of the "big four" SF writers, along with Isaac Asimov, Arthur C. Clarke, and Ray Bradbury.
The book is set on the moon, mainly in Luna City, one of several cities run by the Lunar Authority, a highly rigid and hide-bound bureaucracy based on Earth to mine the moon for the benefit of Earth's citizens, leaving the moon's inhabitants impoverished and unfree. Nor do the citizens of Earth care, since the moon is peopled mostly by convicts sentenced to life terms on the moon and their descendants, called Loonies. Especially since the grain produced on the moon in vast underground caverns and shipped to earth via a huge launch catapult is critical for feeding the Earth's billions of people.
The narrator is Manuel O'Kelly-Davis, who goes by Mannie, a computer technician on contract with the Lunar Authority, who one day discovers the Lunar Authority's main computer has "woken up." The computer, who adopts the name Mike, isn't a bad sort, although he has a childish sense of humor (for instance, sending out a paycheck to one Loonie for $10 billion). Mannie is Mike's only friend; indeed, the only one who knows he is sentient, and Mike controls virtually every vital service provided in the various moon cities (air, water, transportation, finance, etc.). When Mannie's friend, Professor de la Paz, gets him mixed up with a lunar independence movement, along with the beautiful revolutionary Wyoming Knott, Mannie is able to get Mike on their side, giving them a ghost of a chance to defeat the Federated Nations of Earth and earn freedom for the Loonies.
The moon in anarchic society--but not disordered! Because the Lunar Authority doesn't provide law, caring only if the grain shipments keep coming, it's up to the Loonies to determine their own way of living. This is where Heinlein's libertarianism comes in, which this book really explores. Justice, for example, is privately-administered. A judge is someone mutually acceptable to both parties, the fee for hearing a case is negotiated, the defendant chooses whether he wants a jury or not, based partially on if he wants to pay, with payment perhaps scaled to parties’ income. Poor judges don’t get repeat business, competition keeps prices low, balancing of interests ensures justice is achieved. Actually, the way Heinlein describes it makes our own system of justice seem fairly clunky.
The Loonies also have come up with alternative ways of arranging families and romantic matches. Mannie is part of a "line marriage," where a new husband or wife is brought into the family every few years, alternating by gender. Yes, that means there are multiple spouses, ranging in age from late teens to old age. His marriage has been around for more than 100 years, and he points out it works well for a farming family, as his is, because it allows for the accumulation of capital across generations. Like the privately-administered justice system, it may seem weird, but Heinlein describes it in such a way that by the end of the novel it seems quite natural, even preferable in some ways to our own way of doing things.
This book is not for everyone, but those it is for will really get into it. On one level, the story of the revolution itself is pretty exciting, and Mannie, Mike, the Professor, and Wyoming are likable characters who are easy to root for. But deeper than that, it's a novel packed with ideas, expertly presented so you hardly realize Heinlein is showing you how a truly libertarian society could work. It's those multiple levels that make this one of the all-time classic science fiction novels.