Jean-Paul Sartre is the influential writer most known for his existentialist views. A prominent figure in 20th-century literature and philosophy, Sartre espoused the idea that existence precedes essence, emphasizing individual freedom, choice, and responsibility. His works, such as "Being and Nothingness" and "Nausea," delve into themes of absurdity, isolation, and the human condition. His literary contributions and philosophical essays profoundly influenced existentialism and the intellectual discourse regarding human existence, freedom, and meaning in a post-war world.