Why Heinlein is a master of the genre should not be a question to anyone. The craft has been raised to such a high level at a time when sci-fi was often so simplistic, focusing on cheap thrills, gore, and something that basically translated to "fantasy among the stars", damsels in distress and one-sided heroes included. Heinlein, though not alone, changed this. Science-fiction became a genre to be appreciated. For its depth, for its width, for its ability to relay the human experience in such understandable terms under what are often such unusual circumstances. This particular book tells us the story of how the people on the Moon became independent. Though the book is now 55 years old, releasing at a time when humanity hadn't even set foot upon the Moon, it is so believable. AI, space travel, living in low-g environments. Political turmoil and a divided Earth. It all comes into a play and comes together in a fantastic stories with great characters, human or AI.