When upton sinclair committed himself to writing The Jungle, he had no idea how he was going to pull it off, and he ended up improvising all the way. The result was a novel, the first ever to be called “proletarian,” which is far more complex and revealing than is generally understood. We still tend to break the book in two, and read it, as its first public did, for the sensational early chapters, dismissing the rest as a tedious tract. However, taken whole, in light of the story of its conception, composition, and revision, The Jungle comes to look less like an episode in the muckrake movement, and more like a major text of American social fiction, one of those compelling, garbled, perplexing, sometimes amusing encounters between the conventionally literate and the working class, which became a fixture of imaginative life in America by the end of the nineteenth century.