Historical introduction to A Week on the Concord and Merrimack Rivers (1980) in the Princeton University Press edition of The Writings of Henry D. Thoreau
Thoreau's Complex Weave: The Writing of "A Week on the Concord and Merrimack Rivers," With the Text of the First Draft (University Press of Virginia, 1986)
Essays in The Emerson Dilemma: Essays on Emerson and Social Reform (University of Georgia Press, 2001)
Approaches to Teaching Thoreau's "Walden" and Other Works (Modern Language Association, 1996)
The Cambridge Companion to Henry David Thoreau (Cambridge University Press, 1995)
Critical Essays on Henry David Thoreau's "Walden" (G.K. Hall, 1988)
Entries in the Biographical Dictionary of Transcendentalism and the Encyclopedia of Transcendentalism (Greenwood Press, 1996)
articles in various journals, including ESQ: A Journal of the American Renaissance, The New England Quarterly, Studies in Bibliography, Studies in the American Renaissance, and the Walt Whitman Review