Sir Joseph Cook, GCMG (7 December 1860 – 30 July 1947) was an Australian politician and the sixth Prime Minister of Australia. He worked in the coal mines of Silverdale, Staffordshire during his early life, he emigrated to Lithgow, New South Wales during the late 1880s, and became General-Secretary of the Western Miners Association in 1887.A founding member of the Australian Labor Party, Cook was elected to the New South Wales Legislative Assembly as Member for Hartley on 3 July 1891.