Cook, James (1728–1779), a British navigator. Captain Cook accurately charted vast regions of the South Pacific; provided a basis for England's claim to Australia and New Zealand; and developed a diet that prevented scurvy among seamen. Cook was born of farming parents in Yorkshire. He went to sea as a boy and joined the Royal Navy in 1755. His seamanship and diligence soon gained recognition, and four years later he was made master of a naval sloop. From 1763 to 1767 he explored the St. Lawrence River and the shores of Labrador and Newfoundland.

In 1768, with a group of scientists, Cook set out on his first expedition, sailing around Cape Horn. The immediate purpose was to observe the transit of the planet Venus from the vantage point of Tahiti. On this voyage, which continued until 1771, the party went on to explore the coasts of New Zealand and to chart the eastern coast of Australia.

As a result of this expedition, Cook was promoted to commander in the navy and was sent with two ships to determine whether there was a continent at the southern extremity of the earth. Although they did not sight Antarctica, the explorers were the first to cross the Antarctic Circle. During this expedition of 1772–75, Cook sailed around the world far to the south, mapping the South Pacific and other southern areas. By providing the crews with sufficient vegetables, Cook proved that scurvy, a disease caused by lack of vitamin C, need no longer plague men on long sea voyages.

Cook was promoted to captain and on his third voyage of discovery, 1776–78, undertook a search for the Northwest Passage—a linking of the Atlantic and Pacific oceans by way of Arctic regions. He approached from the Pacific side and discovered the Sandwich (Hawaiian) Islands. Although he found no passage through the ice, Cook explored the northwest coast up to the Bering Strait. After his return to Hawaii, he was killed by a native because of a misunderstanding over a missing boat.