Friedrich Nietzsche once identified three approaches to the writing of history: the monumental, the antiquarian and the critical, the last being history “that judges and condemns.” Howard Zinn, who died on January 27 at 87, wrote the third kind. Unlike many historians, he was not afraid to speak out about the difference between right and wrong.

Zinn was best known, of course, as the author of A People’s History of the United States, which since its publication in 1980 has introduced millions of readers to his vision of the American past. Few historians manage to reach a broad nonacademic audience. Those who do generally write Nietzsche’s monumental history, works that celebrate great men (the founding fathers, Abraham Lincoln) or heroic events (the building of the Transcontinental Railroad, World War II). Zinn’s history was different. Through A People’s History and various spinoffs (including a recent dramatization by prominent actors of a collection of documents on the History Channel), Zinn’s public learned about ordinary Americans’ struggles for justice, equality and power.

I have long been struck by how many excellent students of history first had their passion for the past sparked by reading Howard Zinn. Sometimes, to be sure, his account tended toward the Manichaean, an oversimplified narrative of the battle between the forces of light and darkness. But A People’s History taught an inspiring and salutary lesson–that despite all too frequent repression, if America has a history to celebrate it lies in the social movements that have made this a better country. As for past heroes, Zinn insisted, one should look not to presidents or captains of industry but to radicals such as Frederick Douglass, Susan B. Anthony and Eugene V. Debs.

Before writing A People’s History, Zinn published SNCC: The New Abolitionists (1964). This book grew out of his experience teaching at Spelman College, an institution for young black women in Atlanta, and his participation in the civil rights movement. It remains essential reading for anyone seeking to understand the upheavals of the ’60s. Its subtitle is worth noting. At a time when most historians still depicted nineteenth-century abolitionists as neurotic misfits whose agitation brought on an unnecessary war, Zinn identified their campaign against slavery as the beginning of a long, unfinished struggle for racial justice.

A veteran of World War II, Zinn spoke frequently about the horrors of war, lending his voice to those opposed to American involvement in Vietnam and, more recently, Iraq and Afghanistan. He was a passionate critic of the national security system and the militarization of American life.

A few years ago, I lectured at St. Olaf College in Northfield, Minnesota (the hometown of the late, lamented Senator Paul Wellstone). Zinn had been there a few days before, and across the top of the student newspaper was emblazoned the headline Zinn Attacks State. I sent Howard a copy. We laughingly agreed that he could not have a more appropriate epitaph.