From Introduction: "The major purpose of this bulletin, as indicated in the preface by Dr. John W. Finch, Director of the Bureau of Mines, is to give a critical review of the coal-mining methods used in the principal producing countries of Europe, to describe the reasons underlying the adoption of these methods, and to contrast them with coal-mining methods employed in the United States."

From Introduction: "Work on this project was begun early in 1944; and the results with respect to shale oil are reported in this Bulletin. Since this bulletin is only an index to this large repository of ideas relating to the the treatment of shale oil, the material is presented in the form of short notices describing the subject material of each patent, which consist of an abridgment of the patent (if British or Australian) or a typical claim in the case of the United States or foreign patents."