Garry Kasparov is arguably the greatest chess player of all time. From 1986 until his retirement in 2005, he was ranked world No 1. He is also a leading human rights activist and is probably close to the top of Vladimir Putin’s hitlist, not least because he tried to run against him for the Russian presidency in 2007. But for people who are interested only in technology, Kasparov is probably best known as the first world champion to be beaten by a machine. In 1997, in a famous six-game match with the IBM supercomputer Deep Blue, he lost 3½-2½.