Upton Beall Sinclair Jr. (1878-1968), who also wrote under the pseudonyms Ensign Clark Fitch and Frederick Garrison, was a prolific American author who wrote over 90 books in many genres and was widely considered to be one of the best investigators advocating socialist views and supporting anarchist causes. He achieved considerable popularity in the first half of the 20th century. An early success was the Civil War novel Manassas, written in 1903 and published a year later. It was originally projected as the opening book of a trilogy, but the success of his 1906 novel The Jungle caused him to drop his plans. He gained particular fame for The Jungle, which dealt with conditions in the U. S. meat packing industry and caused a public uproar that partly contributed to the passage of the Pure Food and Drug Act and the Meat Inspection Act in 1906.