One evening in May 1866, a half-dozen former Confederate soldiers gathered in a law office in Pulaski, Tenn., and decided to form a club. Seeking a name “suggestive of the character or objects of the society,” especially amusement and recreation, they considered “kukloi,” a derivative of the Greek word meaning band or circle, when someone cried out, “Call it Ku Klux.” The young men added “Klan” to complete the alliteration and the Ku Klux Klan was born.

This story, which first surfaced many years later, may or may not be true. More certain, of course, is the concern that animated the subsequent behavior of the KKK: the extent to which freed people would supplant whites in the emerging social, economic and political order of the “reconstructed” South. It seems clear as well that the meaningless but mysterious name, carnivalesque costumes and rituals, and acts of violence directed at African-Americans and radical Republicans secured the Klan’s reputation as a force to be reckoned with.

In “Ku-Klux: The Birth of the Klan During Reconstruction,” Elaine Frantz Parsons, an associate professor of history at Duquesne University, provides a comprehensive examination of the Klan in the post-Civil War era. Extraordinarily well-researched, her book at times overwhelms readers with details that, Ms. Parsons acknowledges, “may be boring” to everyone but historians. That said, her analysis of the symbols, images and language used by Ku-Kluxers, their supporters and their opponents is often interesting and illuminating. And Ms. Parsons supplies a persuasive analysis of the role of the Klan in ushering in a sense of “the inevitability of white dominance and the tragicomic nature of black aspiration.”

Ms. Parsons suggests, for example, that the Ku-Klux costumes and performative identities (as foreigners, animals and ghosts), situated as they were at the intersection between folk vigilante disguise and contemporary popular entertainment (in parades, circuses, masquerade balls, minstrelsy, novels and theatrical productions), were chosen to push against characterizations of Southerners as backward-looking. Their behavior conveyed that they were unpredictable and uncontrollable. Most important, Ms. Parsons writes, in an era in which African-Americans “were increasingly asserting their own agency,” Ku-Kluxers reclaimed their own manhood and relegated their victims, who tended to be active in formal and informal organizations of freed people, “to passive spectatorship.”

Ms. Parsons demonstrates as well how Republicans and Democrats, in the North and the South, used the Ku Klux Klan to enhance support for their political positions. For Republicans, the existence of a powerful Klan operating with impunity served as a compelling reason to maintain — or even increase — the presence of U.S. Army troops and other personnel in the South. Democrats, by contrast, had a vested interest in minimizing Klan activity as “youthful pranks” or isolated acts of violence. Despite conclusive evidence to the contrary, they often expressed skepticism that the organization existed at all. Ku-Klux, one newspaper editor claimed, was a “mythical maggot of distempered Republican brains.” Our Northern enemies, wrote another, “eagerly believe anything to our prejudice,” and will capitalize on it.

Throughout “Ku-Klux,” Ms. Parsons takes pains to indicate that although the first Klan was not as centralized or institutionalized as its opponents (and non-historians today) believe it was, the circulation of false and exaggerated claims did not make Klan attacks any less real and deadly. And Klan terrorism (and “the idea” of the Klan) produced fear that had enormous consequences on the associational life and political activism of African-Americans and their allies.

“Ku-Klux” concludes with the discomforting observation that, alas, is confirmed by the attention recently given in our presidential primaries to David Duke and white supremacists. The Klan, Ms. Parsons reminds us, “did not materialize out of nowhere, and neither did it really go away.”

Glenn C. Altschuler is the Thomas and Dorothy Litwin Professor of American Studies at Cornell University.

First Published: April 17, 2016, 4:00 a.m.