University of Illinois
University of Illinois: Modern American Poetry
This rich source includes a biography of Edgar Lee Masters (1869-1950 CE), a bibliography of secondary sources, his comments on Spoon River Anthology, a look at him as a trial lawyer and critic, as well as external links.
A&E Television
Biography: Edgar Lee Masters (1868 1950)
This resource provides a very brief biography of the poet, playwright, and novelist.