Article dans une revue: Oliver Hart and Bengt Holmström were awarded the 2016 Swedish National Bank’s Prize in Economic Sciences in Memory of Alfred Nobel for their contributions to the Theory of Contracts. Their works build a theory of firms and organizations that is based on two pillars: (1) Parties exert efforts or incur investments that increase the value of their relationships, but these actions are sometimes hidden, not directly observed, and thus cannot be contractually enforced by courts, and (2) contracts and ownership structures are (imperfect) responses to such informational frictions. Together, the contributions of these authors have paved the way for a complete renewal of the Theory of the Firm and Organizations Theory.