"In nine months of a man's life he can think a lot of things, from the loftiest meditations on philosophy to the most desperate longing for a bowl of soup–in total accord with the state of his stomach."

This passage accurately characterizes the contents of The Motorcycle Diaries; indeed, the book ranges widely from humorous, everyday observations to discourses on history and archaeology, from reflections on justice and revolution to descriptions of excruciating hunger and cold. Additionally, this passage–the third sentence of the introduction–is the reader's first encounter with Guevara's lighthearted and humorous writing style. While parts of the book are quite serious, Guevara maintains this light touch throughout and his writing is often wry, sarcastic, and witty.

"The person who wrote these notes passed away the moment his feet touched Argentine soil again. The person who reorganizes and polishes them, me, is no longer, at least I am not the person I once was. All this wandering around 'Our America with a capital A' has changed me more than I thought."

Despite the gaiety of tone and youthful spirit that pervade The Motorcycle Diaries, the book is also an important historical and personal document–the story of Guevara's transformation from the carefree young medical student with a longing for faraway places to whom we are introduced at the beginning of the book to Che Guevara, the revolutionary we know from world history. In this passage, Guevara acknowledges the transformational power of his journey; by the end of the book, he is ready to give his life for the revolution.

"The first commandment for every good explorer is that an expedition has two points: the point of departure and the point of arrival. If your intention is to make the second theoretical point coincide with the actual point of arrival, don't think about the means–because the journey is a virtual space that finishes when it finishes, and there are as many means as there are different ways of 'finishing.' That is to say, the means are endless."

Guevara's journey is both a physical one, with geographical start and end points, and a spiritual one, defined just as much by his inner progress, from who he was at the start to who he is at the end.