Born in 1813 in Copenhagen, Denmark, Søren Kierkegaard is often regarded as the father of existentialism. His strict religious upbringing — as well as enduring a broken engagement and the deaths of his parents and five of his seven siblings before he turned 30 — deeply shaped his philosophies on faith, guilt, and the struggles of human existence. Kierkegaard wrote prolifically under his own name and several pseudonyms. Supported by an inheritance from his wealthy father, his output spanned novels, psychological musings, satire, philosophy, literary criticism, and, primarily, Christian theology; his critique of institutional religion and his belief in personal faith was considered groundbreaking.

Though Kierkgaard’s eccentricities gave him a level of local notoriety in his lifetime, his many works — including seminal reads Either/Or: A Fragment of Life (1843), Fear and Trembling (1843), and The Sickness Unto Death (1849) — only gained real momentum posthumously. Kierkgaard worked until his death in 1855 at the age of 42.