Ida Tarbell’s classic write-around of the world’s only billionaire:
He was a silent boy — a silent young man. With years the habit of silence became the habit of concealment. It was not long after the Standard Oil Company was founded, before it was said in Cleveland that its offices were the most difficult in the town to enter, Mr. Rockefeller the most difficult man to see. If a stranger got in to see any one he was anxious. "Who is that man?" he asked an associate nervously one day, calling him away when the latter was chatting with a stranger. "An old friend, Mr. Rockefeller." "What does he want here? Be careful. Don't let him find out anything." "But he is my friend, Mr. Rockefeller. He does not want to know anything. He has come to see me." "You never can tell. Be very careful, very careful." This caution gradually developed into a Chinese wall of seclusion. This suspicion extended, not only to all outsiders but most insiders. Nobody in the Standard Oil Company was allowed to know any more than was necessary for him to know to do his business. Men who have been officers in the Standard Oil Company say that they have been told, when asking for information about the condition of the business, "You'd better not know. If you know nothing you can tell nothing."