Jean-Paul Sartre's publication of 'Being and Nothingness' in 1943 defined existentialism, asserting that 'existence precedes essence.' Sartre argued that individuals are condemned to be free, bearing the weight of their choices and responsibilities. This work profoundly influenced philosophy, literature, and psychology, prompting discussions about human existence and the nature of freedom.

Defined the committed literature (littérature engagée) and the bleak, absurd landscapes of mid-century verse, focusing on alienation and radical choice. Poets such as Samuel Beckett and Paul Celan drew on Sartre's existential themes, exploring the human condition in a fragmented world.