TEXT IN FRENCH. Nihilism, as it is defined by Nietzsche, has not ceased being a challenge to the literature of the 20th century. With a significance and an originality out of the ordinary, Milan Kundera has investigated the existential state resulting from the basic problem as follows: Which possibilities does one have when caught in the feeling that everything is worth something and nothing is worth while at the same time? The present study interprets the meaning and importance of Kundera's questions through an analysis of 'The Unbearable Lightness of Being' examining both how the work presents itself aesthetically and its thematic development.