is a foundational work of existentialist literature, written as a fictional memoir of an unnamed, bitter, and alienated narrator living in 1860s St. Petersburg, known as the "Underground Man". The book is a fierce critique of rationalism, utilitarianism, and utopian ideals prevalent in 19th-century Russia, asserting that human nature is fundamentally irrational and thrives on free will, even if it leads to self-destruction