Upton Sinclair's 1906 novel The Jungle describes the harsh conditions faced by immigrant workers in Chicago's meatpacking industry in the early 20th century. Based on Sinclair's undercover investigation of the industry, the book tells the story of a Lithuanian immigrant family seeking the American Dream but finding poverty, oppression, and spoiled meat. The novel brought attention to issues like long work hours, low pay, and unsanitary practices and helped pass new food safety laws, though Sinclair primarily aimed to promote socialism. The Jungle was influenced by the large wave of European immigration to the U.S. at the time and tensions between social classes that led to the growth of socialism as a movement advocating for workers' rights and reforms.