Nausea is written as a diary begun by Antoine Roquentin in January of 1932. Roquentin, a thirty-year-old man, has been living in the small French seacoast town of Bouville for the past three years, during which he has been researching and writing a biography of the Marquis de Rollebon, an eighteenth-century political figure. Roquentin lives alone in a one-room apartment near the train station. Before moving to Bouville, he had spent many years traveling throughout the world.

Roquentin begins writing the diary in order to record a subtle change he has noticed in his perceptions of himself and the world around him. He is disturbed by his own consciousness and by uncertainty about the significance of his life, and he is questioning the meaning of the existence of objects and people in the world. He has recently begun experiencing episodes in which he is overcome with...