On 20 August 1968, hundreds of thousands of soldiers, dozens of thousands of tanks and armoured vehicles, and hundreds of military aircraft of the Warsaw Pact armed forces invaded Czechoslovakia in an operation code-named Danube. It was the largest military undertaking in Europe since 1945. Starting with a description of the history of Czechoslovakia, especially after the communist takeover of power in 1948, this volume describes the birth and development of the Prague Spring in 1968 and an attempt to reform the communist system from within. It recounts the hostility this process encountered on the part of the Union of Soviet Socialist Republics (USSR/Soviet Union), and its allies within the Warsaw Pact, and provoked a split in the Kremlin about solutions for the resulting 'Czechoslovak problem'. The crisis that developed throughout the spring and summer of 1968 led to the military intervention. While paying special attention to the military and strategic aspects of the Czechoslovak crisis, this volume also provides a blow-by-blow account of its impacts upon the Czechoslovak armed forces and the Warsaw Pact. The subsequent military operation - codenamed Operation Danube - is described in all of its components, including the airborne and ground aspects, and the political operation that supported it. Within only 24 hours, the Soviet and Warsaw Pact forces secured the entire territory of Czechoslovakia, de-facto overrunning the local armed forces in the process. The Czechoslovak population organised non-violent resistance, thus highlighting the political aspects of the intervention. However, it was hopelessly out of condition to prevent the ultimate downfall of the so-called 'Prague Spring', and the related hopes. Nevertheless, the application of military power against a popularly-supported political reform marked a turning point in the Cold War, and forever changed the balance of power in Central Europe. Guiding the reader meticulously through the details of the forces involved, their organisation and equipment, Operation Danube offers a uniquely in-depth account of the invasion of Czechoslovakia and is profusely illustrated with more than 100 photos, maps, and exclusive colour artworks.