Sartre’s first novel focuses on Antoine Roquentin, an introspective historian who undergoes an existential crisis. Roquentin loses confidence in established values of ordinary life. His recognition of the absurdity of life precipitates problems in all his relationships, including his relationship with himself. Roquentin records the shifts in his perceptions and the struggle to restore meaning to his life in a continuous present, free of lies. Besieged by metaphysical doubts, he tries to cleanse himself of “the sin of existing.” The physical manifestation of his angst is nausea. “Nausea” is one of the central texts of 20th-century existentialism.