HISTORY:Thinking the Twentieth Century By Tony Judt, with Timothy Snyder William Heinemann, 414pp. £25

TONY JUDT was one of the most opinionated thinkers of his time. He refused to sacrifice moral ire to academic neutrality, and he was not afraid of what anyone thought. Opinions, for this bold historian, were matters of life and death. They counted. And nowhere more so than in the particularly tormented century he wrote about, ranging from the first World War and the Russian Revolution to the collapse of the three main modern ideologies: fascism in the 1940s, communism in the 1980s and capitalism in the 1990s.

Judt called himself an intellectual rather than an academic. And one can see why. He worked at many distinguished universities – Cambridge, Paris, Berkeley – but was always at odds with his superiors. At Cambridge he received his doctorate with scarcely a word exchanged with his director, and it was not much different in Paris and California, where the authorities in his field were constantly miffed by his insubordinate theories. His lectures were packed and usually off topic. If history, he twisted it to politics; if politics, to culture; and so on. He wouldn’t sit still and never stopped, right up to the end, when he lay dying of a degenerative disease that left only his brain intact. He kept thinking. He died in August 2010, at the age of 62. Thinking the Twentieth Century is his last testament.

It is a book of conversations. Conducted during the final months of his life with a brilliant young historian, Timothy Snyder (author of the acclaimed Bloodlands), Judt’s valedictory verdicts on the last century are apt and arresting. The dialogue format makes for a compelling read, and the sense that time is running out brings sharp focus to what is being said. No time for beating around bushes or hedging bets. This is history straight up.

Judt takes his tune from the French writer Émile Zola, whose famous J’Accuse . . . ! in the Dreyfus affair marked the birth of the modern committed intellectual, a legacy running up to inspirational thinkers such as Václav Havel and Adam Michnik at the end of the 20th century. These dissenting minds believed in “living in truth”. Judt takes them seriously and distinguishes between two kinds of truth: little truths about what actually happens and big truths about what certain people say happens. Bush on Iraq and the Israeli political party Likud on Palestine were two of his recent targets, earning him the scorn of many establishment commentators, as witnessed in the controversial columns of the New York Review of Books.

Judt’s critical interventions were as multiple as his lives, from political Marxist and European historian to American moralist and committed social democrat – the last considered the best he could get. His ultimate goal was civic responsibility in a just community. This hugely erudite and multifaceted book is a plea for “decent life” in the wake of a betrayed century.

Judt writes like an insider-outsider. He slips inside a particular event, absorbing its conflicts and complexities, before passing back out again to think and write. And it is this unique dialectic of empathy and distance that lends his work its persuasive edge. When writing of Nazi Berlin or Vichy France, or critically engaging with contemporary catastrophes, Judt never simply surveys. He thinks on his feet, and his thinking is action.

This is a book without fuss or footnotes. One of its singular strengths is that each chapter is preceded by a biographical section in which Judt speaks of his intellectual journey. He resisted this strategy at first, but Snyder insisted. And Snyder was right. The narrative clips along, placing each historical period in the context of Judt’s adventurous life.

Born in London in 1948, Judt was a child of postwar socialist Britain. His father, a polyglot of Polish-Jewish origin, had lived in Dublin for many happy years before moving to England in 1936, when the family lingerie business failed. The young Judt studied French history at Cambridge before heading off to the École Normale Supérieure, where he conducted special, and largely independent, research on modern French history. The wars, and the grandes illusions that fuelled them, were his special target. Then there was the time spent as a Zionist utopian in kibbutzim in Israel, where he even served in the army. But he was soon disenchanted and left for the US, where he became a citizen and pursued a brilliant university career on both the east and west coasts, establishing himself as one of the most outspoken public intellectuals of recent times. A trenchant critic of fascism and Stalinism, Judt also had no compunction about turning his fire on the neoliberal capitalism of Reagan or the neoimperialism of Bush, not sparing, on a more minor scale, the PC policies of postmodern academe. Few escape his savage indignation.

And yet neither Judt nor Snyder cedes to despair. They know that thinking can be daring as well as dangerous. They firmly believe that the life of the mind can lead to a mindful life. And they settle for no less.

Richard Kearney is professor of philosophy at Boston College, in Massachusetts. His most recent book, Anatheism, was published by Columbia University Press, 2009