Can you understand the soul of a man who never hesitated to take steps that would have the effect of hoodwinking people, who would use every trick of the markets to mislead, and who was at the same time scrupulous never to utter a direct lie on the most insignificant matter? Manderson was like that, and he was not the only one. I suppose you might compare the state of mind to that of a soldier who is personally a truthful man, but who will stick at nothing to deceive the enemy. The rules of the game allow it; and the same may be said of business as many business men regard it. Only with them it is always wartime.

Chapter XV: "Double Cunning" - Trent's Last Case (1912)