Glaciology, now broadly defined as the study of ice in all forms, is often regarded as a some what esoteric subject, though it takes little thought to dispel the notion. The sheer quantity of ice on Earth, together with its past and present effects on geophysical processes and human activity, commands attention, while at the same time ice itself proves to be an ideal material for studying processes and properties that involve almost the entire field of classical physics. With the belated wedding of academic ice physics and glacier study, glaciology is contributing significantly to geophysics and materials science, as is evidenced by continued support for research both in the laboratory and in the field. Some 90 per cent of the world's ice is contained in the Antarctic ice sheet, a glacier of continental proportions about which little was known prior to the International Geophysical Year. Since 1957 the United States, by maintaining through the National Science Foundation a vigorous Antarctic glaciological program, has made an impressive contribution of knowledge which is reflected in part by the papers and references in this volume. By entering heartily into the spirit of international cooperation that has so brightened recent Antarctic endeavors, the U.S. has made a further contribution: to human understanding and to the diffusion of knowledge. This too is reflected here, for more than half of the authors came into the program from foreign countries. Much has been learned, but more remains to be studied, since, as research should, the investigations have raised new questions as fast as old ones were answered. Before efforts are renewed in force, however, there should be some assessment of the broad problems and of the methods available for their solution; in this respect the following collection of papers should be helpful. Glaciology, now broadly defined as the study of ice in all forms, is often regarded as a somewhat esoteric subject, though it takes little thought to dispel the notion. The sheer quantity of ice on Earth, together with its past and present effects on geophysical processes and human activity, commands attention, while at the same time ice itself proves to be an ideal material for studying processes and properties that involve almost the entire field of classical physics. With the belated wedding of academic ice physics and glacier study, glaciology is contributing significantly to geophysics and materials science, as is evidenced by continued support for research both in the laboratory and in the field.