During World War One the Scandinavian countries played a dangerous and sometimes questionable game; they proclaimed their neutrality but at the same time pitched the two warring sides against one another to protect their import and export trades. Germany relied on Sweden, Norway and Denmark for food and raw materials, while Britain needed to restrict the flow of these goods and claim them for herself. And so the battle for the North Sea began. The campaign was ferociously fought, with the Royal Navy forced to develop new tactical thinking, including convoy, to combat the U-boat threat. Many...