The novel is filled with descriptions of corruption and greed. Balzac quotes the price for everything, from the room rents on different floors of the boarding house to the cost of a meal or a horse-drawn carriage. Money rules the world after the success of capitalism through the Industrial Revolution, and has also infiltrated aristocratic society.
Rather than studying his law books, Rastignac tries a shortcut to wealth by having himself introduced in high society by his cousin, Madame de Beauséant. There he meets Goriot's daughters, Anastasie (married to rank, a count) and Delphine (married to money, a banker) and falls in love with the second one. Vautrin, at the same time, pushes him to court a young woman in the boarding house, Victorine, whose family fortune is blocked only by her brother - of course, he offers to clear the way for Rastignac. The student balks at the idea of murder, but listens attentively to the lessons about the harsh realities of modern society that Vautrin teaches him.
Old Goriot is supportive of Rastignac's courtship of his daughter, but dies after suffering a stroke. Neither of his daughters visits him at his deathbed (ashamed as ;they are of their pauper of a father) and only Rastignac attends the funeral - before heading off to the apartment of Delphine for another rendez-vous. He sure is climbing the social ladder, and shouts out at the city of Paris: "It's between you and me now!"
Le Père Goriot is a "bildungsroman:" the initially naive Rastignac is tutored by Vautrin, Madame de Beauséant and others in the truth of society and the ruthless strategies required for success. First repulsed by these unpleasant realities, Rastignac eventually embraces them. The novel gave rise to the French expression "Rastignac" for a social climber willing to use any means to better his situation.