In January 1952, a 23-year-old Argentine medical student and his friend, a biochemist, set out on a motorcycle from Buenos Aires to explore South America, making their way west, north, and finally east through the continent until they eventually reached the Venezuelan coast. It was a journey of discovery for the two, the kind of adventure Jack Kerouac was having at about the same time in a car crossing the U.S. and that he immortalized in the novel On the Road. The medical student and his friend also wrote about their trip, one in a diary at the time and the other in a memoir later. None of this might have attracted much attention if the medical student hadn't been Ernesto Guevara de la Serna, aka Ché Guevara, who went on to become a famous revolutionary and whose image, in beard and beret, continues to be a symbol for activists on the far left. Walter Salles' film The Motorcycle Diaries recreates the journey, which opened Guevara's eyes to the struggles of the poor in South America, and Gustavo Santaolalla's score is also a musical journey through the same territory. Santaolalla, an Argentine rock musician who previously scored 21 Grams, is only nominally concerned with authenticity in his musical cues, most of them played by his five-piece band. He gets a folkish flavor in much of his music, but he also falls back on the electric guitar, sometimes played with a rock slant, not exactly what you'd expect to hear in the South American countryside in 1952. He also throws in a few tunes by others, notably a mambo by Pérez Prado and the pretty "Al Otro Lado del Río" by Jorge Drexler, which closes the soundtrack album. An orchestral score would have been inappropriate for a film of this kind, and this one instead evokes the native music of the countries through which Guevara passed without being slavishly traditional.