This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book focuses on changing contextual factors within the economic and political environment that have bearing upon the performance of the political system. It examines the transitional phase from differing points of view and with a variety of emphases. The book suggests that the middle sectors of Mexico's society have scarcely been placated by the decidedly lackluster commitment made by the regime to its own program of political reform. It explores contemporary developments in the Mexican authoritarian political framework in light of the ruling party's strategy of political liberalization and considers the performance of the political system within the highly constrained economic context. The book discusses the program of political liberalization in Mexico initiated in the latter part of the 1970s, assessing its purposes and weighing its long range impact upon the political system.