"There are no second acts in American lives," F. Scott Fitzgerald famously wrote in "The Last Tycoon," perhaps the most self-evidently ridiculous sentence in our literary canon. Frederick Douglass, one of our more brilliant and towering political figures, carved out numerous acts in his lengthy Shakespearean life, from enslaved man to silver-tongued orator to global celebrity. But as David W. Blight, a Yale historian, notes in his authoritative, meticulously researched biography, Douglass revised and tweaked his own story in three autobiographies. Reinvention was essential not only to Douglass' survival but also to his shaping of our national character.

Born in Tidewater, Md., in 1818, Frederick Bailey barely knew his mother, Harriet, who died when the boy was 8. His father was assuredly white, although Douglass was never certain whether his own master, Aaron Anthony, had raped Harriet: "Slavery does away with fathers as it does away with families," he opined.

The boy's staggering intellect manifested early, as he was shuttled around the Lloyd family's empire, where Anthony worked, eventually serving the openhearted, devoutly Christian Sophia Auld, in Baltimore. Auld taught Douglass how to read and to write, bequeathing the tools with which he'd confront the scourge of racism. (His imposing adult physique also impressed audiences.) After working odd jobs on the Baltimore docks, lining his masters' coffers, Douglass hatched an ingenious plan to escape on a train, in plain sight, his wife, Anna, following behind.

Blight's arc traces the familiar lines of Douglass' story — his years as a fugitive; his career as a public speaker, supporting Anna and their five children; his tour of the British Isles (partly imagined in Colum McCann's recent novel, "TransAtlantic"); the founding of the North Star, the premier abolitionist journal — but assiduously fleshing it out with rich detail and context.

There hasn't been a biography of Douglass in a quarter-century, and Blight, editor of annotated editions of Douglass' work, illuminates the heightened tensions of the antebellum era, the orator's firm conviction that only a brutal civil war would end slavery, his "difficult, if eventually historic" relationship with Lincoln. This is scholarship on an epic yet accessible scale, occasionally dry but always vital, as Douglass' writing, activism and contradictions speak directly to us today.

Blight taps previously neglected archives to re-create Douglass' later years, his rise to cherished eminence grise and familial stresses. (After Anna's death he married Helen Pitts, a white feminist 20 years his junior, provoking rifts with his children.) He lobbied tirelessly for women's suffrage alongside his second wife and Ida B. Wells. And as Blight writes, "He continued to preach unapologetically to blacks about self-reliance," setting the stage for W.E.B. Du Bois and the Rev. Martin Luther King Jr.

"Frederick Douglass: Prophet of Freedom" is nothing if not a doorstop, and Blight's exhaustive, donnish approach may not suit every reader's palate. But it's a commanding account of a singular life, a sumptuous portrait of a crusader unyielding in his pursuit of racial justice.

Hamilton Cain is the author of "This Boy's Faith: Notes From a Southern Baptist Upbringing," and a member of the National Book Critics Circle. He lives in Brooklyn.

Frederick Douglass: Prophet of Freedom
By: David W. Blight.
Publisher: Simon & Schuster, 888 pages, $37.50.