Berkman and other members of the anarchist community raced uptown to see what had happened. Meanwhile, Murphy disappeared.

The bomb peeled the top two floors off the building, exposing to a crowd of onlookers what remained of the apartment of Louise Berger. A member of the Anarchist Red Cross and an editor of Emma Goldman's Mother Earth Bulletin, Berger had lent the five anarchists her apartment while they built their bomb. Now she stood next to Berkman and her colleagues, gazing up at her demolished home.

She didn't get much sympathy from the press. "That only the I.W.W. agitators and their women sympathizers were killed as a result of the explosion seems little short of miraculous in view of the extent of the ruin wrought by the dynamite," wrote the Times reporter. The police, who had a history of clashes with the I.W.W., kicked off their investigation by interrogating Berkman and Berger, who claimed not to know anything about the plot.

As police sifted through the evidence, they noticed a link between the dead radicals. All four had attended courses at the Ferrer Center, an alternative school in Harlem, as part of its adult education program. What in the world was going on at that school?

Associates of the Ferrer Center swore over and over that the school had had nothing to do with the attack. The Ferrer Center had an adult education program, yes, but it also taught grade-school age children. The administrators of the day school claimed to know nothing about the bomb. Nonetheless, the evidence was there. The four plotters, other anarchists readily admitted, had recently attended lectures at the school.

So the cops staked out the Modern School, their best and most concrete lead. While the children of the day school took their lessons and played in a nearby park, they waited, hidden, to see if something would turn up.

***

Two years earlier, in a trench outside a fort in Catalonia, Spanish monarchists executed the founder of the first Modern School. Francesc Ferrer i Guàrdia, an anarchist, had opened a progressive grade school in Barcelona with the goal of cultivating free thinkers. Eight years later, he found himself accused of sedition.

They held a trial of sorts. A junior military officer, given less than a day to review Ferrer's brief, served as defense. The prosecution, said William Archer -- a pro-Ferrer British journalist who wrote about the teacher's death for McClure's -- failed to call any witnesses. It didn't matter. At one point, an official told Ferrer he had read some of his writing on the Modern School. The sedition charge, he hinted, might have come from nothing more than some teaching materials.

In the ideological wars of the first half of the century, the minds of students had become one more battleground. If you could teach them your way, Ferrer believed, you could change the future. And in his eyes, if the classroom was another terrain for political conflict, then the stasis of the Spanish education system in the 20th century probably favored conservative and right-wing forces.