The Motorcycle Diaries Author is Ernesto Guevara, a revolutionary figure in Latin America. He was an Argentine Marxist revolutionary, physician, author, guerrilla leader, diplomat and military theorist. Guevara's life story was documented in his memoir The Motorcycle Diaries, which was published posthumously in 1993. The book details the journey of Guevara and his friend Alberto Granado across South America during the early 1950s.