Henri Laborit gives an introduction to the physiology of the brain, and also briefly describes his own background. Summary biographies of three fictional characters are given in parallel to his own: Jean Le Gall is born into a comfortable middle-class family on an island in the gulf of Morbihan in Brittany and pursues a career in radio and politics; Janine Garnier, daughter of left-wing working-class parents in Paris, runs away from home to become an actress, but later switches career to be a fashion adviser; René Ragueneau rebels against the old-fashioned outlook of his farming family in Torfou, in Maine-et-Loire, and studies accountancy before becoming an executive in a textile factory in Lille; a company merger forces him to take a new job in Cholet, away from his wife and children.
Laborit expounds his ideas on four main types of animal behaviour, grounded respectively in consumption, escape, struggle, and inhibition. The lives of the three fictional characters intersect at various points (Jean in an affair with Janine, René negotiating with Janine about the future of his job) and each of them faces moments of critical life-changing decision. At these moments they are seen as self-identifying with the image of a popular star in French cinema (Jean with Danielle Darrieux, Janine with Jean Marais, and René with Jean Gabin).
Laborit comments on the conflicts arising from pursuit of dominance among individuals and defensive reactions to it, and reflects on the need for better understanding of the human brain