Adequate treatment of so large and so extensively developed a district as that of Leadville necessitates a voluminous report, in which the practical questions of prime interest to the commercial world can not be systematically answered until the data on which they depend are discussed. Many readers will no doubt wish to turn at once to the chapter on ore reserves, which will give them an appraisal of the district, without bothering with geologic detail. For those who wish a brief general account, a summary of the principal chapters of the report is presented below.