Operation “Hazen” was an IGY expedition, organized by the Canadian Defence Research Board to carry out scientific studies in the Lake Hazen area of northern Ellesmere Island, from April 1957 to August 1959. From April to August 1957, a party of six carried out glaciological, glacial-meteorological, seismic, and survey studies on Gilman Glacier, and two geologists worked out from Hazen Camp, the main station on Lake Hazen. From August 1957 to April 1958, a party of four meteorologists wintered at the base camp. The third phase, from April to August 1958, involved a continuation of the 1957 studies on Gilman Glacier, an extension of these studies to the ice cap to the north of Lake Hazen, and a co-ordinated study of the Lake Hazen basin and of other parts of northern Ellesmere Island. The latter included meteorological, geological, limnological, geomorphological, botanical, zoological and archaeological work by twelve members of the expedition stationed at the base camp. In the summer of 1959, a limited programme of glaciological, meteorological and botanical research was conducted by a small party on Gilman Glacier. During the spring and autumn re-supply operations, the expedition received support and co-operation from the Royal Canadian Air Force, the United States Coast Guard, the United States Navy, the United States Air Force, and (for a week in 1958) from a “Supercub” aircraft flown by Dr Terris Moore of Waterville, Maine.