The Communist Party of Spain (PCE) has significantly shaped Spanish politics over the last few decades. As the leading force of the anti-Franco opposition, the PCE played a central role in the democratization process following Franco's death. To this day, it remains the third strongest political force as part of the United Left (Izquierda Unida). This book is the first comprehensive account of the political, ideological, and organizational development of Spanish communism from the late phase of the Franco regime to the present day. The first part examines the strategy and politics of the PCE in the anti-Franco underground and during the democratic transition. The second part analyzes the emergence, development, and politics of Izquierda Unida. With this alliance, founded in 1986, the PCE succeeded in shaping the turning point, unlike many other Western European communist parties.