📕 The Jungle is an Upton Sinclair novel portraying the lives of immigrants in the United States and in the Chicago meatpacking industry during the early 20th century in particular. The book depicts working class poverty, the absence of social programs, harsh and unpleasant living and working conditions.Upton Sinclair was a Pulitzer Prize-winning who wrote over 90 books, best known for his muckraking novel, The Jungle.