Civil Disobedience and the Underground Railroad
http://www.calliope.org/thoreau/thurro/thurro1.html
Provides broader historical context for Thoreau's essay, in addition to biographical facts about his political activism.
Henry David Thoreau, Civil Disobedience
http://usinfo.state.gov/usa/infousa/facts/democrac/19.htm
Complete text of the essay, preceded by helpful introduction.
Civil Disobedience Criticism
http://www.vcu.edu/engweb/transcendentalism/authors/thoreau/critonrcg.html
Documents the history of political criticism on Civil Disobedience from the 1920s on.
Civil Disobedience: A Philosophical Perspective
http://www.earlham.edu/~peters/writing/civ-dis.htm
Outlines philosophical objections to, in conjunction with defenses of, the legitimacy of civil disobedience in a democracy.
