Admiral Chester William Nimitz (February 24, 1885 – February 20, 1966) was the Commander in Chief of Pacific Forces for the United States during World War II. He was the United States' leading authority on submarines, as well as Chief of the Navy's Bureau of Navigation in 1939. He served as Chief of Naval Operations (CNO) from 1945 until 1947. He was the United States' last surviving Fleet Admiral.