A French historian in his thirties, solitary, intelligent, and undergoing a perceptual crisis that is also a philosophical awakening. Roquentin is not a hero — he does not act, he witnesses. His defining characteristic is a kind of ruthless intellectual honesty that prevents him from adopting the comforting fictions available to him. By the end of the novel he has abandoned his career, his relationship, and his social world. He is left with the possibility — not the certainty — of writing something. Sartre uses him to dramatize what authentic existence costs.

A self-educated former prisoner of war who is reading through the entire library alphabetically. He represents the humanist bad-faith response to contingency: the adoption of a ready-made ideology (love of Man, faith in Progress) that provides meaning and social belonging without requiring an authentic confrontation with freedom. His exposure and humiliation at the end of the library thread is Sartre's most brutal demonstration that bad-faith structures are fragile — they work until they don't.

Roquentin's former partner, an actress obsessed with staging 'perfect moments.' She had, before Roquentin, a theory of how to redeem contingent existence through aesthetic construction. By the time of their reunion, she has abandoned the theory and is living in a kind of managed nullity — going through the motions of a life without belief in it. She is Roquentin's mirror image: the same crisis, a different prior strategy, an equally inconclusive outcome.

The eighteenth-century diplomat whose biography Roquentin is writing. He never appears — he exists only as archival fragments, interpretations, and Roquentin's projections. His function in the novel is as the object onto which Roquentin has displaced his existential need for purpose. Rollebon is what you study when you are not ready to study yourself.