The journalist and author Bryan Burrough has spent the last five years researching and writing a book on what he correctly perceives to be an oddly neglected topic: the scourge of left-wing terrorism, much of it by the Weather Underground, during the 1970s. According to FBI statistics, the United States experienced more than 2,500 domestic bombings in just 18 months in 1971 and 1972, with virtually no solved crimes and barely any significant prosecutions.

In Days of Rage, Burrough seeks to counter what he views as the successful efforts by these former terrorists to craft “an image of the group as benign urban guerrillas who never intended to hurt a soul”—and whose “only goal” was “to damage symbols of American power, such as empty courthouses and university buildings, a Pentagon bathroom, the U.S. Capitol”—when, in fact, they were “murderous.”

Murderous, yes, but also nuts. Mark Rudd—famous for leading the 1968 Columbia University protests, in which students advanced the cause of social justice by rifling through the university president’s private files and destroying years of scholarly research—recalled in his memoir that what he termed the “most notorious Weatherman period” consisted of “LSD acid tests, orgiastic rock music, violent street actions, and…orgies to prove our revolutionary love for each other.” At one of these meetings, Weather Underground leader Bernardine Dohrn made her infamous speech about the need to be “crazy motherfuckers and [scare] the shit out of honky America,” before paying tribute to the Manson family: “Dig it! First they killed those pigs, then they ate dinner in the same room with them. They even shoved a fork into the victim’s stomach! Wild!”

Burrough reminds us that the Weather Underground was hardly alone in its idiotic beliefs. Much the same could be said, with proper caveats, about the other groups he covers, who were convinced that if they attacked the right symbols of power—robbed the right banks, broke the right windows, kidnapped the right heiresses, and murdered the right number of police—“the revolution” would surely follow. These groups included the Black Panthers, the Black Liberation Army, the Symbionese Liberation Army, the New World Liberation Front, the FALN, the “Family,” and the United Freedom Front.

Days of Rage is simultaneously disturbing and annoying. It’s disturbing because of the remarkable combination of stupidity, ignorance, and arrogance shown by these extremists. Absolutely nothing they did helped bring about a more equitable or compassionate country (leftist terrorism was even more destructive in Italy and Germany). Yes, they inspired a lawless reaction from the Nixon administration and the FBI, which resorted to criminal behavior of its own to stamp them out. And yes, they captured the occasional headline—most spectacularly when three members of the Weather Underground blew themselves up in a Greenwich Village townhouse. But every time they called for solidarity from those they considered natural allies—the poor, the oppressed, the discriminated-against—they were met with apathy, and often contempt.

But Burrough’s story is also annoying, because it does so little to explain what drove these people to such self-destructive extremes. We learn nothing of their childhoods. We read next to nothing about the politics of the era, with barely a mention of the madness under way in Indochina. Burrough does a decent job of describing the nuts and bolts of underground life (and the FBI’s remarkable inability to capture any of them). But he doesn’t even try to interrogate the sources of their descent into fanaticism.

It was popular in those days to quote The Wretched of the Earth, Frantz Fanon’s paean to the “cleansing” properties of revolutionary violence. This theme was further explicated in Jean-Paul Sartre’s egregious preface (“Make no mistake about it; by this mad fury, by this bitterness and spleen, by their ever-present desire to kill us, by the permanent tensing of powerful muscles which are afraid to relax, they have become men”). But Burrough’s subjects barely mention Fanon, and Sartre not at all. We hear more about blaxploitation flicks like Shaft and Sweet Sweetback’s Baadasssss Song. (The violent sexism of some characters in these films was particularly appealing to certain would-be revolutionaries.) The Weather Underground’s single attempt at an ideological statement, a manifesto called “Prairie Fire,” reads like self-parody. It is dedicated, I kid you not, to Sirhan Sirhan (Robert Kennedy’s assassin), among others, and explains: “We need a revolutionary communist party in order to lead the struggle, give coherence and direction to the fight, seize power and build a new society.”

Rarely did anyone in any of these groups raise objections to the violence they were bent on. According to Howard Machtinger, an early Weather Underground leader, “If all Americans were compliant in the war, then everyone is a target. There are no innocents.” Their concern was less the death of bystanders than the insufficient spectacle that too little violence would produce. “The problem with Weather wasn’t that people disagreed with our ideology,” Machtinger says. “It was that they thought we were wimpy. The sense was, if we could do something dramatic, people would follow us.” These lunatics actually believed that “Third World countries would rise up and cause crises that would bring down the industrialized West, and we believed it was going to happen tomorrow, or maybe the day after tomorrow, like 1976.”

Today, most of the crazies are on the right—most prominently in the Middle East, North Africa, and South Asia—albeit with the same violent machismo running rampant. But while left-wing terrorism has mostly disappeared, the largely forgotten story in Days of Rage should lead us to ask—lest history repeat itself as violent farce—why the most extreme, however nutty, are so frequently able to hijack movements purporting to fight for social justice.