The Man Who Would Be King by Rudyard Kipling

This novella follows the journey of two British adventurers in British India who become kings of a remote part of Afghanistan. After persuading local tribes to follow them through a mix of bravado and technological superiority, their rule is initially successful. However, their ambition leads to overreach when one of them decides to take a wife, breaking a local religious taboo. Their once-loyal subjects turn against them, leading to a dramatic and tragic conclusion that serves as a cautionary tale about the dangers of imperialism and the limits of hubris. The 3146th greatest book of all time