At the beginning of World War I, it became clear that the navy would play a crucial role. The English naval blockade cut off Germany's supplies. The Imperial Navy, poorly equipped compared to the Royal Navy, resorted to cunning tactics in its desperation: it armed seemingly harmless merchant ships with heavy weaponry and sent these apparently civilian vessels, with constantly changing disguises and on inventive routes, to cruise the world's oceans to engage the enemy and seize prizes. This modern form of piracy between warring parties was almost unique in the 19th century. Naturally, the British were not oblivious to these plans, leading to a cat-and-mouse game that began in the German ports of Kiel and Wilhelmshaven and then spanned nearly the entire globe. This book recounts the situation.