The moon is a harsh mistress by Robert A Heinlein
Set it an overpopulated future, this story takes place mostly on Earth's moon. Agricultural development of the moon, through ice mining and hydroponic grain production feeds the population of earth. originally, the inhabitants of the lunar colonies come from deportation, similar to the Australian concept, but as the generations progress, and convicts serve out their sentences, they are forced by physiological changes to remain on Luna. This leads to a completely different society, being exploited by earth as a source of cheap agricultural labour. The exploitation of the workers on the moon prompts several people, Manuel, Wyoming, and Professor Bernado de la Plaz (Prof) to formulate a revolution. Luna will be free!
Enter Mike. short for Mycroft, the fictional brother of Sherlock Holmes. also, he is a super computer. he controls much of the maintenance of Luna. also, he just woke up, and attained sentience.
lots of cool, realistic sounding sci fi action, definitely possible science. The novel has some definite socialist roots, but simply because of the fact that every human even hinges and builds on all of our past events. wars of the future will be like wars of the past, for similar reasons, with similar messages.
Luna is free, earth tries to pacify, Luna fights back, Luna wins, Luna remains free. Prof dies at the end, and so does Mike. except Mike doesn't really die. his circuits are all still there, he just stops talking, responding, and interacting.
I think that the book is a tale of what it means to be alive, and about mike's journey into consciousness, set against a parallel story of a nation/moon's rise to independence and national consciousness.
so much message in these sci fi books, you have no idea.