Bradford, the late E. G. Patterson of Titusville, the late Henry D. Lloyd, author of Wealth 01. Commonwealth, William Hasson of Oil City, and P. C. Boyle, the editor of the Oil City Derrick, have collections of value, and they have all been most generous in giving me access to their books. But the documentary sources of this work are by no means all printed. The Standard Oil Trust and its constituent com panics have figured in many civil suits, the testimony of which is still in manuscript in the files of the courts where the suits were tried. These manuscripts have been examined on the ground, and in numerous instances full copies of affidavits and of important testimony have been made for permanent reference and study. I have also had access to many files of private correspondence and papers, the most important being that of the officers and counsel of the Petroleum Producers' Union from 1878 to 1880, that covering the organisation from 1887 to 1895 of the various independent companies which resulted in the Pure Oil Company, and that containing the material prepared by Roger Sherman for the suit brought in 1897 by the United States Pipe Line against certain of the Standard companies under the Sherman anti-trust law.