This book cover image released by Norton shows “Kent State: An American Tragedy” by Brian VanDeMark. Norton via AP

More than a half century has passed since Ohio National Guard members opened fire on college students during a war protest at Kent State University, killing four students and injuring nine others.

The description of the nation, then split over the Vietnam War, leading up to the 1970 tragedy echo today's politics and divisions in many ways. In “Kent State: An American Tragedy,” historian Brian VanDeMark recounts a country that had split into two warring camps that would not and could not understand each other.

“It was a tense, suspicious, and combustible atmosphere that required only a spark to ignite a tragedy,” VanDeMark writes.

VanDeMark succeeds at helping readers understand that atmosphere, creating a chilling narrative of the spark and ensuing tragedy at Kent State. Within less than 13 seconds, 30 guardsmen fired 67 shots at protesters in an event where “the Vietnam War came home and the Sixties came to an end,” he writes.

With a straightforward writing style, VanDeMark provides both a micro and macro look at the events leading up to the massacre — examining the growing dissent against the U.S. involvement in Vietnam and how it rippled across Kent State's campus.

VanDeMark relies on a host of new material, including interviews with some of the guardsmen, to reconstruct the protests on campus and the shooting. He also recounts the investigations and legal fights that ensued following the shooting.

“Kent State” portrays a campus that grappled for years with its legacy, with no official memorial to the slain students erected on campus until two decades later, in 1990. A new visitors center devoted to the shooting that opened in 2012 suggested an emerging consensus about the tragedy, writes VanDeMark, whose work may contribute to that consensus as well.