In writing the story of Military Intelligence I feel as though I were picking my way along a narrow and slippery path which is bordered on either side by precipices and is in places obscured by fog. On the one hand, I am in danger of unconsciously overemphasizing the mysterious and sensational aspects of the subject; on the other, of making it appear more commonplace and prosaic than it really is. And, at every few steps, I find my progress hindered by the veil of secrecy which necessarily enveloped certain activities of the division during the war, and which it has not been deemed wise entirely to lift with the return of peace. And there is still another difficulty. The public has in a large measure obtained its conceptions of military intelligence work from the novels of Sir Arthur Conan Doyle, Mr. Robert W. Chambers, and Mr. E. Phillips Oppenheim. So, if the pages of this narrative are not filled with alluring adventuresses of dazzling beauty, cloaked assassins, secret agents flitting about the countryside in high-powered cars, German barons disguised as head waiters, mysterious signals flashed by night to lurking U-boats, messages written in invisible ink, and midnight meetings in subterranean chambers, my readers will be disappointed and dissatisfied and will probably believe in their hearts that I am holding something out on them. The story depends, after all, on the angle from which you look at it. I know an officer of the Military Intelligence Division who goes about on tiptoe, figuratively speaking, with his finger always on his lips. He is so tight-mouthed that Colonel House seems garrulous beside him. This officer has been of enormous service to his country, and the importance of his work fully justifies the secrecy and mystery with which he surrounds it, yet his duties have been performed at an office desk in Washington, with a table of logarithms at his elbow, and, so far as action and adventure are concerned, his life has been about as exciting as that of a professor of mathematics. I know another man, likewise connected with the Military Intelligence Division, who, assuming the guise of a workman, succeeded in obtaining admission to the councils of the I. W. W. and of criminals operating in the forests of the Northwest, and who did more than any single person, perhaps, to unearth the conspiracy which had for its object the crippling of our airplane programme. For weeks on end he carried his life in his hands, for, had his identity been suspected, he would have met a sudden and mysterious end by knife or bullet. Yet he speaks of his adventures as casually as though he had been in no greater danger than a Fifth Avenue policeman.