It is London's account of his experiences as a hobo in the 1890s, during the worst economic depression the United States had experienced up to that time. He describes his experiences hopping freight trains, "holding down" a train when the crew is trying to throw him off, begging for food and money, and making up extraordinary stories to fool the police. He also tells of the thirty days that he spent in the Erie County Penitentiary, which he described as a place of "unprintable horrors," after being "pinched" (arrested) for vagrancy. In addition, he recounts his time with Kelley's Army, which he joined up with in Wyoming and remained with until its dissolution at the Mississippi River.