Social democracy has long been seen as in crisis, with some predicting its end and others emphasizing its capacity to adapt to changing contexts; this open access book explores the evolution of social democratic thought, identifying the period of 1970s to the 1990s as key decades in marking its transformation. Analysing this evolution through the lens of socialist parties of Southern Europe- including those of SpainPortugal, Italy, France, and Greece - this book argues that the political and ideological trajectories of these parties, their internal and transnational debates, as well as their international engagements, are relevant to understanding the broader history of European social democracy and, more generally, contemporary Europe. Specifically, it investigates how these parties approached, debated, and responded to key issues such as socialist ideological development, the relationship between European security and NATO, relations with the Third World, and the projection of social democracy toward the Global South. The ebook editions of this book are available open access under a CC BY-NC-ND 4.0 licence on bloomsburycollections.com. Open access was funded by Universidad Complutense de Madrid, Universidad de Castilla-La Mancha, Institut François Mitterrand and Fundación Felipe González.