Empires are synonymous with centralized—if occasionally schismatized—hierarchical power structures in which influence is restricted to an economically privileged class retaining its advantages through—usually—a judicious use of oppression and skilled manipulation of both the society's information dissemination systems and its lesser—as a rule nominally independent—power systems. In short, it's all about dominance.

Chapter 1 (p. 91). - Culture series - The Player of Games (1988)