When Robert E. Lee surrendered to Ulysses S. Grant after the Battle of Appomattox Court House on April 9, 1865, the South’s defeat in the Civil War had been all but assured. But as author Kidada E. Williams reminds us in her shattering new book, “I Saw Death Coming,” another insidious shadow war was just beginning. For Black people in the South, the war’s end was merely a false dawn, with more horrors awaiting them.

In her powerful and deeply moving history of the Reconstruction era, Williams, an associate professor of history at Wayne State University, upends the narrative of the post-Civil War era as a redressing of past wrongs, with pockets of white resistance impeding new protections as enumerated in three newly drafted constitutional amendments. Instead, a kind of crypto-Confederacy emerged from the collective rage of a fallen white South that refused to cede an inch to those they had subjugated. Despite the 13th Amendment’s abolition of slavery, the liberation struggle remained a Sisyphean task, as many of the newly freed found no emancipation at all.

“To African Americans, freedom at the end of the Civil War wasn’t simply about being released from bondage,” Williams writes. “It also involved legal certification of Black People’s entitlement to access all the privileges of American freedom.” According to Williams, African Americans’ newly granted legal rights and protections only inflamed a rearguard of militant farmers who had other ideas — and were willing to expropriate by force all that had been legally granted to their former slaves. As Williams tells it, Reconstruction has become a national myth; the new frontier the federal government had ostensibly granted freed people in the immediate postwar era remained well out of sight.

The members of this racist planter class would become marauding obstructionists, using fear and intimidation to roll back postbellum gains, scorching the earth now being carefully tended to by their former slaves. This irruption of violence dovetailed with the rise of the Ku Klux Klan, which began as a social club in Tennessee and then quickly metastasized into a band of white supremacist terrorists.

The new book’s power derives from its eye-level approach, as Williams homes in on several newly freed Black families while they struggle in the months after the war to establish footing on hostile ground, only to find every incremental gain met with violence, every small victory a prelude to further struggle. These freed people, Williams points out, were not just trying to earn a living. New communities had to be raised up from nothing, families made whole again. A new culture, in short, had to take root.