Whatever name the historians gave to the conflicts fought by Sweden and Denmark-Norway, and despite all of the battles, sieges, winter campaigns, and guerrillas, in a wider perspective these events have been often considered a theater of war on the periphery. The struggle for predominance in Europe was not formed up in some hyperborean outlying land, but down in Flanders, Rhineland and Mediterranean. However, even in Northern European countries, the war set its mark on the masses, involving economy, domestic policy and diplomacy throughout the conflicts. After the devastating war against Poland, and Russia, and later The German Empire, Brandenburg and the Netherlands, Sweden was a major Louis XIV’s ally. Both France and Sweden were interested in reducing the Dutch leading roll as a seafaring, commerce nation. Denmark-Norway faced this scenario always in the opposite side. The Swedish army was still regarded as a role model by the contemporaries, and even after the reforms introduced by Gustavus Adolphus, Swedish generals did not cease to develop new military theories, while the state provided itself with an administrative structure capable of supporting the war effort. No less important was the political and military trajectory of Denmark, the nation that more than any other in these years was on the front line against the Lion of the North. The history, organisation, equipment, uniforms and ensigns of the two armies are brought together in a single volume, together with an appendix dealing with the Duchy of Courland.