In the immediate aftermath of its successful revolution, Cuba was heralded by socialist nations as the vanguard of communism in Latin America in the early 1960s. But by the late 1980s, Cuba's inability to adopt the modes of socialist planning and Mikhail Gorbachev's reforms had deeply soured the relationship between Havana and the Soviet-led socialist bloc. While secondary literature often highlights Cuba's political and economic relations with Washington and Moscow, Havana's ideological, political, and economic relations with the Eastern European states have received considerably less attention. This book aims to fill this gap by offering a detailed chronological account of how Cuba's post-revolutionary development was influenced by Eastern European diplomats. Outside of their roles as representatives of their respective states, Eastern European diplomats were entrusted with the task of educating local Cuban leadership in the intricacies of Marxism-Leninism, steering Cuba's governors onto the "correct path of development," helping them eradicate "erroneous ideas" of economic development, and showing them the validity of socialist "morals and ideology." By considering these developments and analyzing firsthand accounts of Eastern European diplomats' experiences in Havana, historian Radoslav Yordanov reconstructs the thinking of Eastern European diplomats and specialists in their dealings with Cuba from the 1959 Cuban revolutionary victory to the 1991 dissolution of the Soviet Union, shedding new light on Cuba's role in the global Cold War.