The First Men in the Moon by H. G. Wells
When penniless businessman Mr. Bedford retreats to the Kent coast to write a play, he meets by chance the brilliant Dr. Cavor, an absentminded scientist on the brink of developing a material that blocks gravity. Cavor soon succeeds in his experiments, only to tell a stunned Bedford that the invention makes possible one of the oldest dreams of humanity: a journey to the moon. With Bedford motivated by money, and Cavor by the desire for knowledge, the two embark on the expedition. But neither are prepared for what they find—a world of freezing nights, boiling days, and sinister alien life, in which they may be trapped forever.