La Onda began with the importation of American and British rock and roll into the Mexican music culture. Throughout the world, rock and roll was spreading and taking root as "a wedge and a mirror for societies caught in the throes of rapid modernization". According to Eric Zolov, author of Refried Elvis: The Rise of the Mexican Counterculture, "rock was a wedge in the sense that it challenged traditional boundaries of propriety, gender relations, social hierarchies, and the very meaning of national identity" which the Mexican PRI (or the Institutional Revolutionary Party) was struggling to define.