information regarding it that is in existence, and no effort was spared to reach his end. The appendix of volume II gives a detailed account of the sources. By special authorization from the Presidents of the United States and Mexico it was possible to examine every pertinent document belonging to the two governments. The search extended to the archives of Great Britain, France, Spain, Cuba, Colombia and Peru, those of the American and Mexican states, and those of Mexican cities. The principal libraries here, in Mexico and in Europe, the collections of our historical societies, and papers belonging to many individuals in this country and elsewhere were sifted. It may safely be estimated that the author examined personally more than 100,000 manuscripts bearing upon the subject, more than 1200 books and pamphlets, and also more than 200 periodicals, the most important of which were studied, issue by issue, for the entire period.[1] Almost exclusively the book is based upon first—hand sources, printed matter having been found of little use except for the original material it contains or for data regarding biography, geography, customs, industries and other ancillary subjects.[1]
The author also talked or corresponded with as many of the veterans as he could reach, and he spent more than a year, all told, in Mexico, where he not only studied the chief battlefields but endeavored, through conversations with Mexicans of all grades and by the aid of foreigners long resident in the country, to become well acquainted with the character and psychology of the people. As the War was fought almost exclusively among them, and its inception, course and results depended in large part upon these factors, the author attaches not a little importance to his opportunities for such personal investigations and to his Mexican data in general.[1]
Probably more than nine tenths of the material used in the preparation of this work is in fact new. No previous writer on the subject had been through the diplomatic and military archives of either belligerent nation, for example. Virtually a still larger percentage is new, for the published documents needed to be compared with the originals. In the printed American reports relating to the battles of September 8 and 13,
