During the lull of the bombing activities my uncle, who stood high with the Pacifist Administration, had obtained permission to fly over Europe, and I, most fortunate of boys, accompanied him. The plane in which we travelled bore the emblem of the World Patrol. On a cloudless day we sailed over the pock-marked desert that had once been Germany and came within field-glass range of Berlin itself. On the wasted, bomb-torn land lay the great grey disc--the city of mystery. Three hundred metres high they said it stood, but so vast was its extent that it seemed as flat and thin as a pancake on a griddle. "More people live in that mass of concrete," said my uncle, "than in the whole of America west of the Rocky Mountains." His statement, I have since learned, fell short of half the truth, but then it seemed appalling. I fancied the city a giant anthill, and searched with my glass as if I expected to see the ants swarming out. But no sign of life was visible upon the monotonous surface of the sand-blanketed roof, and high above the range of naked vision hung the hawk-like watchers of the World Patrol. The lure of unravelled secrets, the ambition for discovery and exploration stirred my boyish veins. Yes, I would know more of the strange race, the unknown life that surged beneath that grey blanket of mystery. But how? For over a century millions of men had felt that same longing to know. Aviators, landing by accident or intent within the lines, had either returned with nothing to report, or they had not returned. Daring journalists, with baskets of carrier pigeons, had on foggy nights dropped by parachute to the roof of the city; but neither they nor the birds had brought back a single word of what lay beneath the armed and armoured roof. My own resolution was but a boy's dream and I returned to Chicago to take up my chemical studies. CHAPTER II I EXPLORE THE POTASH MINES OF STASSFURT AND FIND A DIARY IN A DEAD MAN'S POCKET ~1~ When I was twenty-four years old, my uncle was killed in a laboratory explosion. He had been a scientist of renown and a chemical inventor who had devoted his life to the unravelling of the secrets of the synthetic foods of Germany. For some years I had been his trusted assistant. In our Chicago laboratory were carefully preserved food samples that had been taken from the captured submarines in years gone by; and what to me was even more fascinating, a collection of German books of like origin, which I had read with avidity. With the exception of those relating to submarine navigation, I found them stupidly childish and decided that they had been prepared to hide the truth and not reveal it.