As an essayist, philosopher, ex-pencil manufacturer, notorious hermit, tax protester, and all-around original thinker, Thoreau led so singular a life that he is in some ways a perfect candidate for the historical and biographical treatments made possible by the Historical Guides to American Authors series format. William E. Cain, the volume editor, includes contributions on his relationship with 19th century authority and concepts of the land, which should help the volume''s reach beyond those who read Thoreau for illumination to those general readers who love him for embodying the spirit of American rebellion.