From 1974 until today, PASOK has marked the political life of the country more than any other political entity. But how much do we really know about this party? How do we perceive its political evolution and continuous transformations? What is its relationship with social democracy? Can we make predictions about its future? This book, written by a political scientist, proposes a new synthetic interpretation of the PASOK phenomenon based on the ideological and political hegemony that Andreas Papandreou managed to impose in the post-dictatorship environment. Even after Papandreou's death, his ideological and political legacy continues, to a large extent, to determine the developments in the party he founded. The study of PASOK using tools of systematic empirical research and comparative theoretical analysis highlights critical issues that affect the political process and determine the power game, such as the role of political leaderships and the "rationality" of their decisions, the importance of organization in party development, the construction of ideologies and the formation of collective identities, and the effects of polarization on electoral competition.