The Motorcycle Diaries is, as its title suggests, a record of a motorcycle journey, based on a diary by its author – a young Argentinian medical student – kept during the trip. What makes it remarkable isthat the young medical student who wrote it was Ernesto “Che” Guevara de la Serna, now known as a leader of the Cuban revolution, a guerrilla strategist, a Cuban government official, and a fomenter of revolution in the Congo and Bolivia.

The text documents the journey that made young Ernesto Guevara into the Che we know today: as he travels throughout Latin America with his friend Alberto Granado, he meets workers, the seriously ill, and increasing hardship, and his political and social ideas develop accordingly.

At the beginning of the book, Guevara is restless, out of work, and in need of a break from medical school. Alberto Granado, his 29-year-old biochemist friend, is similarly anxious for a change of scene, in need of a job, and considering an opportunity in Venezuela. He also owns a motorcycle: the ancient, unreliable, and beloved La Poderosa II. The two friends begin daydreaming of a meandering road trip that would take them all the way to North America. What begins as idle fantasy soon becomes reality, as they spontaneously decide to make the trip and begin gathering the necessary documents.

With the bike tuned up and their Chilean visas in hand, the two friends set off. While traveling through Argentina, they rely on family, friends, and acquaintances for food and lodging, and their time on the road is punctuated not only by motorcycle accidents, but also by feasts of meat and wine. Guevara's longing for the road is, however, dampened somewhat by a competing desire to stay behind with his girlfriend, Chichina, whom he and Granado visit. Not long after, however, just as the men are preparing to cross the border into Chile, Guevara receives a letter from Chichina ending their relationship. With this tie broken, he feels freer and commits to the journey, which he records in a lighthearted, freewheeling manner, complete with occasional poetic reveries.

In Chile, Guevara and Granado make the most of Chilean hospitality, enjoying wine and barbecue and getting into mischief. Thanks to an article in a local paper, they become known as “The Experts” on leprosy and many people recognize them and offer help. They also encounter their first real difficulties, as La Poderosa is finally wrecked beyond repair. Having bid goodbye to the motorcycle, the friends must complete the rest of their journey as hitchhikers and stowaways, dependent on the luck and the goodwill of strangers.

They also begin to encounter harsh social realities: exploited miners, who endure dangerous and often fatal conditions in exchange for meagre pay from foreign- and mainly American-owned mines; repressed members of outlawed political parties; downtrodden Indigenous people who work as second-class citizens of their own lands; and poor people whose families cannot afford to care for them when they become seriously ill. Guevara begins to sound a more serious note more often in the text. Cold and hunger, previously absent from his reflections, begin to play a role in his experience.

Guevara and Granado cross into Peru, where they come face to face with the incredible glory of the Quechua warriors and the Inca civilization, whose ruins–among them the magnificent Machu Picchu–still dot the landscape. In Estaque,they see a vision of the past, a valley seemingly untouched by time, where the infrastructure built by the Inca still serves the contemporary population. However, the state of the descendants of these proud tribes creates a stark contrast with this glorious image: dejected, downtrodden, living in abject poverty, misery, and shame, the Indigenous workers Guevara encounters appear to be a completely defeated people. He draws inspiration, however, from a few educated individuals who imagine a better future remains ahead.

In Peru, Guevara and Granado also begin the medical part of their journey in earnest, visiting a leper colony near Lima, seeing firsthand the isolation and poverty in which the patients live, and receiving a heartfelt welcome from patients grateful to be treated like normal human beings. Meanwhile, Guevara himself suffers a serious asthma attack. At the San Pablo leper colony, Guevara again observes inadequate facilities and supplies and patients living in isolation. At his birthday party, he toasts to a united Latin America.

Guevara and Granado sail for Colombia on a raft. After several mishaps and overshooting their destination, they arrive in Bogotá, where they stay only briefly. Next, they head for Venezuela. Guevara suffers another asthma attack; when the narrative resumes, Guevara has recovered from his attack and Granado has departed, presumably in order to take up work in Caracas. Guevara, who is pleased to be returning to his studies but in no particular hurry, wanders around Caracas on his own, missing Granado and observing the lives of the very poor.

The final chapter of the book is a kind of coda, in which Guevara recounts a meeting with an old man who told him that he is a member of the society that is to be destroyed by the coming revolution, and that he will die while taking part in a violent struggle. Guevara reflects on the man's predictions, and says that he knows that when society is divided into two opposing groups, he will be on the side of the people. He is committed to the revolution and happy to make himself a martyr to it in order to bring justice to the people. The carefree young student of Chapter 1 has, seemingly result of his travels, now become a resolute revolutionary.