NEW HAVEN, Conn. — For her first book, “From the War on Poverty to the War on Crime,” the historian Elizabeth Hinton spent years digging through government archives, piecing together how bipartisan tough-on-crime federal legislation had funded an expansion of policing and set the stage for the mass incarceration we live with today.

She had been pursuing a classic directive — follow the money. But shortly after she finished the book, a chance conversation set her archival antennae quivering in a different way.

At a backyard barbecue, she met a political scientist who mentioned he had the archives of the Lemberg Center for the Study of Violence, a short-lived enterprise founded in 1965. Soon she found herself sorting through box after box of newspaper clippings documenting the racial disturbances across the country in the years that followed.

There were reports from the famous uprisings that rocked Watts, Newark, Detroit and other urban centers, including more than 100 that erupted after the assassination of the Rev. Martin Luther King Jr. in April 1968. But there were also articles documenting disturbances stretching well into the early ’70s, in Greensboro, N.C.; Sylvester, Ga.; Ocala, Fla.; York, Penn.; Waterloo, Iowa, and hundreds of other smaller cities and towns — events that had all but fallen out of public memory.

“It was just story after story after story after story,” Hinton recalled earlier this month, during a long interview on her back porch not far from the campus of Yale University, where she is a professor. “It was fascinating to see them come alive.”

Now, in a new book, “America on Fire: The Untold History of Police Violence and Black Rebellion Since the 1960s,” Hinton offers a sweeping account of the turmoil. From May 1968 to December 1972, by her count, some 960 Black communities across the country saw 1,949 separate disturbances, resulting in nearly 40,000 arrests, with more than 10,000 people injured and at least 220 killed.

These incidents, which were often violent, were labeled “riots,” a label which has stuck, including in the scholarship. But Hinton argues that they must be understood as “rebellions” — part of a “sustained insurgency” against entrenched inequality and the harsh policing of the escalating war on crime.