The present account of Alaska Glaciers, by G.K. Gilbert, forms the third of the Harriman Alaska Expedition volumes and the first of the technical series. It is based on observations made by the author in the summer of 1899, while a member of the Expedition, supplemented by information and photographs from various sources, and is illustrated by 106 text figures and 18 plates. The volumes on Geology, Cryptogamic Botany, Insects and Crustaceans are to appear simultaneously with it. The volumes on Nemerteans, Oligochetes, and several other groups of Invertebrates, are ready for the press, and will follow as soon as they can be printed. The two volumes on Phanerogams, or flowering plants, are expected to appear early in the year 1904.<br><br>Acknowledgments are due the Canadian International Boundary Commission, the United States Biological Survey, and, especially, the United States Geological Survey, for the use of photographs and other illustrative material. The editor wishes also to express his appreciation of the drawings prepared for this volume by Mr. W. E. Spader and Mrs. Louise M. Keeler. The frontispiece, plate xi, and a large number of the text figures are by Mr. Spader, while all of the chapter headings are by Mrs. Keeler.