Existentialism is a major twentieth century continental European philosophical movement. In popular accounts, it is sometimes said that existentialism was an expression of postwar ennui that only flourished, and then withered, during the decade after World War II. But this is to confuse existentialist philosophy with “café existentialism”, a cult, vividly described in Simone de Beauvoir’s autobiography , among young Parisians of the time who affected a distinctive style of dress, frequented certain bars, and delighted in iconoclastic behaviour. Philosophical existentialism, by contrast, was not an ephemeral episode, but a body of thought with roots in older philosophical traditions and one that continues …
Cooper, David E.. "Existentialism". The Literary Encyclopedia. First published 08 November 2002; last revised 30 November -1.
[http://www.litencyc.com/php/stopics.php?rec=true&UID=366, accessed 27 April 2015.]