The novel describes Luna’s independence war saturated with society, politics, philosophical, cultural (e.g. enforcing behaviour without laws, presenting different family schemes) and scientific concepts.
Some of those concepts don’t stand the test of time: Heinlein explains the applied cryptographic algorithms which were overhauled 2 years later with algorithms based on heavy computer crunching of prime numbers (DES algorithm); his main computer Mike is quite fascinating, e.g. it has selfawareness (think of 2001 by Clarke!), was able to simulate a video of „himself“ (at a time when computer had no graphic or sound cards) but wasn’t decentralized, yet, as is our internet. But all of those are minor issues because Heinlein couldn’t have known those facts and he did a good job extrapolating what was state of the knowledge at the time of writing.
The chosen language of his protagonists is interesting – it mixes up a pronome lacking English with phrases from Russian and German making up a believable mix in Lunar cultur. Which is problematic as a non-motherlanguage reader, though. And he invented a couple of nice acronyms, like the famous „TANSTAAFL“ (There ain’t no such thing as a free lunch) or the Dinkum Thinkum (i.e. computer) called HOLMES IV („High-Optional, Logical, Multi-Evaluating Supervisor, Mark IV“) or simply „Mike“.
Character development is interesting: The computer Mike wakes up, builds self-awareness, develops practical jokes, learns to lie and to imitate. He is no evil protagonist but more a kind of artificial intelligence pinocchio.
And we have a computer mechanic Manuel „Mannie“ Garcia O’Kelly-Davis going his way from finding this computer to foreign affair minister to general etc. I don’t think that all those roles are very believable.
But I can accept it as a matter of concentrating the quite large story line into a couple of characters without the need of introducing rows of different additional characters.
In summary this is deep in so many aspects that it well deserves 5 stars.