In 1979, Paul Theroux departed from his childhood home in Medford, Massachusetts, and began his train journey from the East Coast of the United States to Patagonia, on the southern tip of Argentina. A seasoned traveler, fluent in Spanish, Theroux brings to life his trip through the northern and southern hemispheres, traveling without a schedule and observing his fellow passengers on the train and people at stops along the way.

In Texas he is astonished at the contrasts between Laredo on the Texas side of the Rio Grande and Nuevo Laredo across the border in Mexico, commenting on society and governments. Traveling through Mexico and Guatemala, he observes the poverty of the Indians and their lack of opportunities. In El Salvador he attends a soccer game and gets caught up in the melee and riots which follow it. In Costa Rica, the cleanest country he has visited, he finds himself stuck on the train with Mr. Thornberry, a New Hampshire tourist so boring that Theroux cannot wait to escape him--only to have Mr. Thornberry "save his life" by offering him a place to stay upon his arrival in Limon. In Panama he meets the "Zonians," from the Canal Zone, and in Cali, Colombia, he meets a married "priest" who cannot tell his devout mother in Belfast that he has "left" the church to marry and have children.

Throughout his trip, Theroux reads classics, particularly enjoying Boswell's Life of Dr. Johnson and Edgar Allen Poe's The Narrative of Arthur Gordon Pym, both of which provide ironic reference points for his own journey. For literature lovers, the most fascinating section occurs in Buenos Aires, where Theroux spends many days visiting blind writer Jorge Luis Borges, who persuades Theroux to read to him. Ironically, one of Borges's favorite novels is The Narrative of Arthur Gordon Pym. As Theroux takes notes on his meetings with Borges, he becomes Borges's Boswell.

More an observer than a participant, Theroux has an unfortunate air of superiority about what he sees and hears. Sparing little sympathy for American and German tourists, he rarely gets excited about his surroundings, expressing genuine emotion only when he talks with three boys, ages ten to twelve, who live in a doorway and scavenge for food because their rural families have abandoned them. Theroux's self-congratulatory attitude gets a bit wearisome, but the picture of Central and South America, thirty years ago, and the section with Borges are unparalleled. With beautiful, carefully observed prose and a great ear for dialogue, Theroux's Patagonia Express is a landmark travel memoir.