Yuri Alekseyevich Gagarin (Russian: Ю́рий Алексе́евич Гага́рин,[1] Russian pronunciation: [ˈjurʲɪj ɐlʲɪˈksʲejɪvʲɪtɕ ɡɐˈɡarʲɪn]; 9 March 1934 – 27 March 1968) was a Soviet pilot and cosmonaut. He was the first human to journey into outer space, when his Vostok spacecraft completed an orbit of the Earth on 12 April 1961.
Gagarin became an international celebrity, and was awarded many medals and honours, including "Hero of the Soviet Union", the nation's highest honour. Vostok 1 marked his only spaceflight, but he served as backup crew to the Soyuz 1 mission (which ended in a fatal crash). Gagarin later became deputy training director of the Cosmonaut Training Centre outside Moscow, which was later named after him.
Yuri died in 1968, when his MiG-15 training jet crashed.
More information:
http://en.wikipedia.org/wiki/Yuri_Gagarin