Upton Sinclair (1878-1968), similar to W.E.B. Du Bois and Helen Keller, is a complicated and interesting historical figure, worthy of serious reflection.
Sinclair is probably best known for his muckraking work in the novel The Jungle. Yet he wrote much more, including a book on early 20th century religion, as well as other novels critical of trends, ideas, and practices of his time and place. Once a member of the socialist party, Sinclair joined the Democratic party so he could run for governor of California in 1934.
Here is Sinclair's American Writer's page, another page about teaching Sinclair, and his PAL page. Here is Sinclair on the radio. Sinclair's papers reside in the Lily Library at Indiana University.
There were several commemorations of Sinclair's 1906 book The Jungle in 2006: read one, and then another.
The most recent biography of Sinclair is Radical Innocent (2006), and another important book also published recently is Upton Sinclair and the Other American Century (2006). the movie "There Will be Blood" is based on Sinclair's 1927 novel Oil!.
[Photo credit here.]