The destructive results of the Chaco War have left an indelible mark on Bolivia and Paraguay. This essay has been undertaken to explore the body of diplomatic material regarding the efforts both to prevent and to halt this useless blood-letting, for it is felt that such an essay would be helpful to any person studying the Chaco dispute in the future. It should be made clear, however, that this is not a definitive bibliography, for it has been limited both to material the author believes would be most useful and to material that can be studied in the United States. Since this essay is concerned mainly with diplomatic aspects, it generally has avoided comment on material dealing specifically with the military phases of the dispute. Such material has been discussed, however, when it also contained information relating to diplomatic matters. The military consideration of the Chaco War deserves a bibliography of its own, for there is a continually growing body of material concerning this subject.