The Moon Is a Harsh Mistress
Ayn Rand's novel "Atlas Shrugged" is a strong (perhaps the strongest) influence with an anti-socialist attitude and an individualist ethic that echoes throughout the genre. Of more direct relevance to the science fiction end of this genre is the work of Robert A. Heinlein, particularly his novel "The Moon Is a Harsh Mistress", which is highly regarded even by non-libertarian science fiction readers.