Bill Alexander (13 June 1910 – 11 July 2000), born as William Alexander, was a leading activist within the Communist Party of Great Britain (CPGB), most known for commanding the British Battalion of the International Brigades during the Spanish Civil War. During World War II he underwent a commissioning course at Sandhurst military academy, graduating top of his year. He then served in Germany, Italy and Northern Africa, during which he was promoted to the rank of captain in the Reconnaissance Corps. Later in life he became an author, the vice-chairman of the International Brigade Association, and the president of London's Marx Memorial Library. Alexander spent the remainder of his life promoting Marxism–Leninism, and was a member of the CPGB until the party was dissolved in 1991.