La Bête humaine is a gripping tale where the instinct of death looms large over the protagonist, Jacques Lantier, a locomotive mechanic. He is acutely aware of how this instinct disguises itself under various appetites, and how the Idea of Death lurks beneath all fixed ideas.

Jacques, a young man, distances himself from women, wine, money, and ambitions, having renounced his instincts. His sole focus is his machine. He understands that the cerebral fissure introduces death into all instincts, working through them. At the origin or end of every instinct, it is about killing, and perhaps also being killed.

Zola, in this novel, powerfully evokes life at the end of the Second Empire in France, where society seemed to be hurtling into the future like the new locomotives and railways it was building. While expressing hope that human nature evolves through education and gradually frees itself of inherited evil, he constantly reminds us of the beast within.