An eccentric scientist and a desperate businessman launch a sphere to the moon, only to discover a complex subterranean civilization. Mr. Bedford, seeking financial salvation, joins forces with the brilliant but erratic physicist Dr. Cavor to construct a vessel capable of reaching the lunar surface. Their arrival on the moon reveals a desolate exterior hiding a vast, interconnected world beneath the crust. The narrative, presented primarily through Bedford's perspective, documents their struggle to survive and communicate with the insectoid Selenites. As they navigate the physical constraints of low gravity and the logical constraints of an alien social structure, the protagonists face the consequences of human intrusion into an established extraterrestrial society.

Readers frequently highlight the contrast between the pragmatic, self-interested Bedford and the detached, intellectual Cavor as a central driver of the narrative tension. Discussion often centers on the book's role as a critique of British imperialism and the dangers of unchecked scientific advancement. Critics note that while the pacing reflects the conventions of early twentieth-century speculative fiction, the world-building remains remarkably inventive for its era. The thematic focus on the rigid, caste-based society of the Selenites continues to generate debate regarding the author's views on social organization and human nature. Many readers appreciate how the story balances the wonder of space exploration with a sobering look at the potential for human conflict in new environments.