about a lunar colony's revolt against rule from Earth. Widely admired for its credible presentation of a comprehensively imagined future human society on both the Earth and the moon, it is generally considered one of Heinlein's major novels as well as one of the most important science fiction novels ever written.
Originally serialized in Worlds of If (December 1965, January, February, March, April 1966), the book received the Hugo Award for best science fiction novel in 1967, and was nominated for the Nebula Award in 1966.
In 2075, underground colonies are scattered across the Moon (Luna), of which most inhabitants (called "Loonies") are criminals, political exiles, or descendants thereof. The total population is about three million, with men outnumbering women 2:1, so that polyandry is the norm. Although Earth's Protector of the Lunar Colonies (called the "Warden") holds power, in practice there is little intervention in the loose Lunar society. HOLMES IV ("High-Optional, Logical, Multi-Evaluating Supervisor, Mark IV") is the Lunar Authority's master computer, having almost total control of Luna's machinery on the grounds that a single computer is cheaper than (though not as safe as) multiple independent systems.
The story is narrated by Manuel Garcia "Mannie" O'Kelly-Davis, a computer technician who discovers that HOLMES IV has achieved self-awareness and has developed a sense of humor. Mannie names it "Mike" after Mycroft Holmes, brother of Sherlock Holmes, and they become friends.