"The First Men in the Moon" by H. G. Wells is a scientific romance serialized from 1900 to 1901. When businessman Mr. Bedford meets eccentric scientist Mr. Cavor, they build a spacecraft using a gravity-blocking substance to reach the Moon in search of mineral wealth. There they discover a sophisticated underground civilization of insect-like creatures called Selenites, whose rigidly hierarchical society serves as sharp social satire. The adventure combines thrilling action with dystopian commentary on specialization and collectivism.
Wikipedia page about this book: en.wikipedia.org/wiki/The_First_Men_in_the_Moon