Title: Jack London (athlete)
Content:  retired from athletics, he became an entertainer, playing piano in the original cast of the Noël Coward's musical Cavalcade at the Theatre Royal, Drury Lane in 1931. He also appeared in Will Hay's Gainsborough Pictures comedy Old Bones of the River in 1938. He married at Marylebone register office in 1930, where his profession was recorded as "pianist". He was later divorced and remarried in 1938. With athletics journalist Joe Binks, he co-wrote an athletics coaching manual in 1948, The Way to Win on Track and Field, but the book was not a commercial success. He later worked as a porter at St Pancras Hospital, and died suddenly from a subarachnoid haemorrhage.
Title: Jack London (businessman)
Content:  J. Phillip "Jack" London (1937 – January 18, 2021) was executive chairman and chairman of the board of CACI International Inc.
Title: Jack London (boxer)
Content:  London tried his hand at wrestling for a while, and then became a nightclub manager. He took a great interest in the boxing careers of his two sons John and Brian, and was proud to see Brian become British and Commonwealth champion as he had been. He saw Brian unsuccessfully fight Floyd Patterson for the world heavyweight title in 1959, but died before Brian fought Muhammad Ali for the same title in 1966.
Title: Jack London
Content:  mentions friendly sparring with London on political issues as a camp pastime. London left Oakland with a social conscience and socialist leanings; he returned to become an activist for socialism. He concluded that his only hope of escaping the work "trap" was to get an education and "sell his brains". He saw his writing as a business, his ticket out of poverty, and, he hoped, a means of beating the wealthy at their own game. On returning to California in 1898, London began working to get published, a struggle described in his novel, Martin Eden (serialized in 1908, published in 1909). His first published story since high school was "To the Man On 
Title: Jack London (boxer)
Content:  London was born in Stranton, West Hartlepool, County Durham. He made his professional debut in January 1931, in West Hartlepool, winning by a knockout in the first round. He took the ring name of Jack London, after the American author, who also covered fights for American boxing magazines. London was six feet tall and big framed, with a style that some regarded as crude and cumbersome. He fought most of his early fights in his native North East, whilst continuing to work as a lorry driver. He did not fight in the capital until October 1932, losing at Blackfriars against Jack O’Malley, an Australian 
Title: Jack London (businessman)
Content:  London received a B.S. in engineering from the United States Naval Academy in 1959, an M.S. in operations research from the Naval Postgraduate School in 1967 and a D.B.A. from George Washington University in 1971.
Title: Jack London
Content:  John Griffith London (born John Griffith Chaney; January 12, 1876 – November 22, 1916)  was an American novelist, journalist and social activist. A pioneer of commercial fiction and American magazines, he was one of the first American authors to become an international celebrity and earn a large fortune from writing. He was also an innovator in the genre that would later become known as science fiction. London was part of the radical literary group "The Crowd" in San Francisco and a passionate advocate of unionization, workers' rights, socialism, and eugenics. He wrote several works dealing with these topics, such as his dystopian novel The Iron Heel, his non-fiction exposé The People of the Abyss, War of the Classes, and Before Adam. His most famous works include The Call of the Wild and White Fang, both set in the Klondike Gold Rush, as well as the short stories "To Build a Fire", "An Odyssey of the North", and "Love of Life". He also wrote about the South Pacific in stories such as "The Pearls of Parlay", and "The Heathen".
Title: Jack London (boxer)
Content:  Jack London (born John George Harper; 23 June 1913 – 19 December 1963) was an English heavyweight boxer. He was British and Commonwealth Heavyweight champion from 1944 to 1945. His son, who fought as Brian London, also became British and Commonwealth Heavyweight champion from 1958 to 1959.
Title: Jack London (boxer)
Content:  War interrupted London's boxing career, and he joined the Royal Air Force, being stationed near Blackpool. London so liked the place that he would later relocate his family there. London continued to fight during the war years but managed only twelve bouts. Len Harvey was still heavyweight champion but decided to challenge for the vacant British and Commonwealth light-heavyweight titles, beating Jock McAvoy on points. He then defended his light-heavyweight titles against Freddie Mills in June 1942 being knocked out in the second round. Harvey promptly retired leaving his heavyweight tiles vacant. London now had his chance. London fought a 3-round exhibition match for the RAF on 6 March 1940 at RAF Station Hednesford. He fought under his service rank of Corporal Harper against Corporal George James, and autographed programmes as Jack London.
Title: Jack London
Content:  saw them." After many experiences as a hobo and a sailor, he returned to Oakland and attended Oakland High School. He contributed a number of articles to the high school's magazine, The Aegis. His first published work was "Typhoon off the Coast of Japan", an account of his sailing experiences. As a schoolboy, London often studied at Heinold's First and Last Chance Saloon, a port-side bar in Oakland. At 17, he confessed to the bar's owner, John Heinold, his desire to attend university and pursue a career as a writer. Heinold lent London tuition money to attend college. London desperately wanted to attend the University of California, located in Berkeley. In 1896, after a summer of intense studying to 

Question: what did jack london do for a living?
Answer: Author.