To many, the Black Lives Matter movement started in August 2014, when protests erupted in Ferguson, Missouri, after a white police officer shot and killed an unarmed black teenager. But while the movement coalesced around the street marches in Ferguson and then spread to places like Baltimore, Cleveland, and Chicago, the declaration that supplied its name was coined considerably earlier: in 2013, shortly after George Zimmerman was acquitted of murder in the death of Trayvon Martin.

On the day of Zimmerman’s acquittal, a Bay Area activist by the name of Alicia Garza took to Facebook. “I continue to be surprised at how little Black lives matter,” she wrote. “And I will continue that. [S]top giving up on black life.” The death of Michael Brown in Ferguson may have been the national tipping point, the moment when Americans were jolted awake by this new rallying cry. But it was Garza and her fellow activists, Opal Tometi and Patrisse Cullors, who helped popularize the phrase as a hashtag on Twitter and Tumblr one year earlier. Movements often have these kinds of indeterminate beginnings—several, at different moments in time, until they get everyone’s attention—and today, in fact, there are so many iterations of Black Lives Matter that it is perhaps most accurate to describe the protests not as a movement but as a set of movements, each with different locally based groups, and without a clear leader or group of leaders.

In his new book “They Can’t Kill Us All,” Washington Post reporter Wesley Lowery sets out not only to track the latest developments in Black Lives Matter, but also to search for the movement’s deeper roots. For Lowery, although BLM protests originated with the recent police killings in the United States—his book takes its title from a sign spotted in Ferguson—he also wants us to recognize that the politics animating these protests have long been around. Lowery traces the movement’s origins to the hope of a “post­racial” America that was symbolized by Barack Obama’s election, and which has now proved to be little more than a phantasm of campaign rhetoric and political punditry. Having once hoped that the election of the first black president meant that the tide of race relations in America might begin to turn, many young black Americans were forced to face the reality—by one high-profile police shooting after another—that living in a world in which they’re treated like their white contemporaries remains an impossibility.

The persistence of police violence against young black people, and the often-racist backlash that followed Obama’s election, initiated this new generation into a cycle that has characterized America’s fraught racial history: A period of optimism born out of a spectacular political moment—the Emancipation Proclamation; Reconstruction; the civil-rights movement of the 1960s—is then followed by a period of reaction and retrenchment. This narrative of youthful idealism followed by frustration and despair is the crux of Lowery’s book, and he believes that the second half of this cycle is now in full swing. But while Black Lives Matter arose in a moment of disappointment and grief, it has for the past four years also helped to inaugurate a new era in the struggle for racial justice.

Wesley Lowery began his career on the metro beat at The Boston Globe. He mostly covered murders and street crime and also reported on the Boston Marathon bombings. But his ambition was to cover national politics, and when he moved to The Washington Post, he set his sights on the 2016 presidential race.

Lowery’s beat shifted, though, shortly after Brown’s death and the protests that followed. The Post sent him to Ferguson; he got arrested even while brandishing a press pass, and soon found a new beat: police brutality and the protests that were emerging in its wake. “Not since the Boston Marathon bombings a year and a half earlier had I covered a story for which there was such intense, immediate appetite,” he writes, later adding: “Police shootings aren’t uncommon, and as a reporter who is professionally acquainted with hundreds of other reporters, images of an angry vigil of grieving residents weren’t particularly out of place in my social media feeds. But even in those early posts, Mike Brown’s death just felt different. The crowds gathered near this young man’s body emanated a guttural anguish. It was clear even then, for those paying attention, that this communal anger would not be easily muted or contained.”

“They Can’t Kill Us All” is the outcome of Lowery’s past two years covering this anguish. He spends the first three-quarters of his book focused on several high-profile police killings: Brown in Ferguson; Tamir Rice in Cleveland; Walter Scott in North Charleston, South Carolina; and Freddie Gray in Baltimore. But while his book is ostensibly about these deaths and the local protests that they inspired, Lowery also has larger ambitions, ranging widely across race relations and racial violence in the United States, including the slaying of nine black churchgoers in Charleston, South Carolina, by a young white man; the removal of the Confederate flag at the South Carolina statehouse by an African- American woman named Bree Newsome; and the emergence of a national movement, or set of movements, responding to the call to arms of Black Lives Matter.

Lowery insists that the story of Black Lives Matter’s roots and intentions is often misunderstood at best and, at worst, purposefully muddied in order to discredit the movement and its leaders. Conservative talking heads have likened BLM and the young black people protesting police brutality to the Ku Klux Klan, arguing that the protesters are perpetuating violence against the police and, more broadly, against white people. Liberal pundits have also been guilty of misrepresenting the movement, seeking to link it to the Democrats—even though many of its leaders have made it clear that BLM isn’t tied to any political party.

Lowery’s book therefore tries to offer a corrective: Movements often have many different origin stories, and his careful behind-the-scenes reporting offers insight into how the various grassroots campaigns converged into what is now often referred to as a single protest movement. He also wants us to discard whatever preconceived notions we have about Black Lives Matter and learn about the nuances and complexities involved in the making of a movement. What happened in Ferguson, Cleveland, and other cities wasn’t anything new; it was just slowly being unveiled to the rest of the public. For centuries, black people in America have struggled for equality, and Black Lives Matter is yet another extension of that struggle. In fact, as BLM has emerged as a national movement, it has become linked with many other issues related to racial justice, from voting rights and mass incarceration to economic inequality and barriers to health care and education—all issues that concern the broader American left.

Many mainstream-media outlets have missed this larger context. Instead of trying to understand how the protests in St. Louis or Baltimore are linked to a much longer history of political struggle, journalists often descend on these cities to get a sensational photo or to break breathless news reports about the confrontations between police and protesters. Rather than looking at the long-standing patterns of police harassment or examining the ways in which these municipalities rely on the frequent ticketing of their black citizens for funds, many newspapers have run stories that indict the victims of police violence, not the officers who killed them or the larger system in which they operate. “And by focusing on the character of the victim,” Lowery writes, “we inadvertently take the focus off the powerful and instead train our eyes and judgment on the powerless.”

Lowery also takes the media to task for overstating the importance of their role in social movements. It’s true that without journalists covering the civil-rights movement, many Americans might not have been persuaded of the justness of its cause. But Lowery believes that reporters often exaggerate their influence on the shaping of social movements.

One can hear a bit of self-criticism here as well. After all, Lowery is himself a journalist who hopes that his reporting may help provide a fairer and more accurate account of Black Lives Matter. In this way, these critical asides come not from a frustrated outsider, but from a respected mainstream journalist attempting to change the way his colleagues report on the movement as a whole.

The book tells a bleak story, but Lowery concludes on a relatively optimistic note. Although the nation’s future looks uncertain and there is much work left to do, in the end, he insists, both the rallying cry and the activism of Black Lives Matter will endure. (Of course, Lowery wrote his book before the election of Donald Trump, so he can be forgiven for not adopting a more ominous tone.) And by certain measures, the movement has been a notable success: BLM protests have been able to put and keep the issue of police brutality at the forefront of the national conversation; the movement has forced politicians to begin to speak the language of Black Lives Matter; and because of public pressure in the wake of Ferguson and Baltimore, a small number of police officers have been charged with shooting unarmed citizens.

But the police killings of unarmed black Americans continue. Each new shooting has seemed like a turning point to activists, an incident far too egregious to be ignored. But almost all of the high-profile police killings have led neither to prison sentences nor reforms. In South Carolina, Michael Slager, the white cop who shot an unarmed and fleeing Walter Scott in the back, was tried for murder, but the jurors couldn’t reach a verdict and the judge was forced to declare a mistrial, allowing Slager to be released pending a new trial. A few months after Scott was killed, University of Cincinnati Police Officer Ray Tensing fatally shot Sam DuBose after pulling him over for a missing license plate—but, as in the case of Scott’s killing, the jury deadlocked and a mistrial was declared.

More cases in which justice will be delayed or denied are certainly on the horizon; for each gain in police reform, there will be another glaring example of why more is needed. The cycle between hope and despair today seems to be in overdrive; each morning we awake to a country that is simultaneously more disheartening and more hopeful than the day before. The election of a president who ran a xenophobic, race-baiting, and ethno-nationalist campaign will mean even greater accelerations, as new protest movements emerge, only to find the space for social change dramatically shrinking.

In this way, the new era for America’s racial-justice movement seems not unlike previous ones. In the 1960s, while black Americans often protested injustice and police brutality with rallies and marches, white Americans terrorized these mostly peaceful protests with threats and acts of vigilante violence that went ignored by the local authorities. Likewise, while politicians like John Kennedy and Lyndon Johnson helped usher in sweeping civil-rights reforms, they were followed by the likes of Richard Nixon, Barry Goldwater, and George Wallace, who responded to these reforms with the dog-whistle demonization of black people and anyone who stood with them. Plenty of Americans let their disdain for the civil-rights activists be known then—often with the same kind of rhetoric and images used against Black Lives Matter.

Because he’s a reporter first, Lowery writes much of “They Can’t Kill Us All” in the evenhanded and straightforward register that one expects of contemporary reporting. But hints of emotion nonetheless break through. At one point, Lowery confesses that he was close to crying when he was assigned to fly out to North Charleston after Scott’s death. “I didn’t want to get on this plane,” he writes, “I didn’t want to spend days telling yet another story of a black man gunned down.” But despite his growing sense of dread as he continues to report on the police shootings, Lowery’s book is written mostly from a position of hope. While many of his peers have advanced a grimmer view when discussing the cycles of African-American history, Lowery finds a cause for optimism in our era’s developing racial-justice movement. After the grand jury in Ferguson chose not to indict Officer Darren Wilson, many warned of rioting; instead, protesters took to the streets in droves to denounce this miscarriage of justice.

As we settle into the next four years of Trump’s presidency, it’s hard to embrace fully Lowery’s sense of hope and possibility. But the quiet optimism underlying his book is itself an act of protest in our dark times. As the Ferguson protesters, quoting Kendrick Lamar, insisted to Lowery: “We gon’ be alright.”