The 20th-century writer known for his work exploring the absurdity of human existence is Albert Camus. His philosophical essays and novels, such as "The Stranger" and "The Myth of Sisyphus", delve into themes regarding the meaning of life, freedom, and the human condition. Camus presents the idea of the "absurd," which reflects the conflict between human desire for purpose and the indifferent universe. His thought-provoking works challenge readers to confront existential dilemmas and the search for meaning amidst chaos.