The central theme of the novel is the fight for political freedom. The lunar colonists' struggle against Earth's oppressive rule highlights the importance of self-governance and the right to determine one's own destiny. This theme is explored through the characters' efforts to establish a new, independent society based on principles of liberty and justice.

The novel examines the relationship between humanity and technology, particularly through the character of the self-aware supercomputer, Mike. Mike's development of consciousness raises questions about what it means to be human and the ethical implications of artificial intelligence. This theme encourages readers to consider the potential and limitations of technology in shaping our future.

Heinlein emphasizes the importance of personal responsibility in the quest for freedom. The characters in the novel must confront their own beliefs and actions as they navigate the challenges of revolution. This theme underscores the idea that individuals have the power to effect change and must take ownership of their choices and their consequences.