Book excerpt: On 9 April 1940, German forces invaded Denmark, and then Norway, in an attempt to secure the vital mineral resources of Scandinavia for their war industry. This assault, Operation Weserübung, represents the first joint air-land-and-sea campaign in the history of warfare, and was the only such campaign planned, launched, and completed by the three services of the Wehrmacht. It also included the use of the rarest of German armoured vehicles, the Naubaufahrzeug NbFz.A/B (PzKw V/VI) experimental 'land battleship'. This book describes the events of this tumultuous campaign of World War II (1939-1945) that not only led to Winston Churchill's appointment as British Prime Minister, but also saw the crippling of the German Kriegsmarine as a fighting force, as it was reduced to a fleet of submarines and a handful of heavy warships used as commerce raiders.