One of Ralph Waldo Emerson's aphorisms defines "The American Scholar" as "Man Thinking." Ralph L. Rusk, in his biography of Emerson (1949), provided his own, somewhat more specific definition of a scholar when he called Emerson's "Historical Discourse" for the 1835 bicentennial of Concord, Massachusetts, "probably the greatest effort Emerson ever made at gathering and checking facts in the manner of a scholar." Later, in "Emerson and the Stream of Experience" (1953), Rusk went so far as to "blame" Emerson because "he did not always wait patiently for evidence to accumulate before making his announcements." These statements dramatize the contrasting temperaments of the meticulous, orderly Rusk--the best of scholars according to his own definition--and the Emerson whose motto was, at least sometimes, "Whim." In his edition of Emerson's letters (1939) and then in the biography Rusk made sense out of a farrago of mostly unpublished materials and brought Emerson to life for...