BOOK REVIEW / JOURNALISM : Humanity Lies Behind Fierce Face of Nationalism : BLOOD AND BELONGING: Journeys Into the New Nationalism <i> by Michael Ignatieff</i> ; Farrar Straus and Giroux, $21, 256 pages.

Berlin’s wall came down and a dozen others sprouted like poisonous mushrooms: marking off the Krajina Serbs from the rest of Croatia, tortuously sketching the intricate three-way bloodshed in Bosnia, outlining the ominous divisions in the Serbo-Albanian Kosovo, and crisscrossing a minefield of actual or potential nationality conflicts in the former Soviet Union.

Michael Ignatieff, son of a Russian-born father and English-born mother, had always believed that “the tide was running in favor of cosmopolitans like me.” Among urban Western intellectuals and professionals during the ‘70s and ‘80s, “a post-national state of mind was simply taken for granted.” But when the nation-states of the Soviet Empire crumbled, they crumbled the other way: not in a cosmopolitan coming-together, but in fierce nationalist fragments.

Ignatieff had his van hijacked just past a U.N. checkpoint by a band of armed Serbs, pale, sweating and reeking of slivovitz, who accused him of spying because they had seen him talking to Croatians on the other side of the barrier.

“This was the moment I began to understand what the new world order actually looks like: paramilitaries drunk on brandy,” Ignatieff writes at the start of “Blood and Belonging.”

His book tells of visits to six present-day nationalisms, some warring, one or two simply painful. It is partly reportage; partly a reflection on what he sees and on the questions that trouble him and that elude those of us who live in comfortable, settled societies.

How did the bitter hatred and atrocious violence spring up so suddenly? Where does the passion come from? What is its nature? What part is a profound and even noble human need, and what part an ugly aberration? And are any of us really proof against it?

“Blood and Belonging,” Ignatieff tells us, is not the work of a solitary traveler and cogitator. It came from a TV series, filmed by crews of cameramen, producers and arrangers in Yugoslavia, Germany, Kurdistan, Ukraine, Quebec and Northern Ireland.

Ignatieff is the reporter and thinker, and both his reportage and reflections are useful and often illuminating. Only, we lose something, as tends to happen with books that grow out of TV projects.

The writer’s presence, his voice, his specific gravity--and Ignatieff is an excellent writer--are somewhat dissipated: They thin out at times or become overly gestural. Camera and words work passably well together--even if someone else is using the camera--but the words always seem a bit caged.

This said, Ignatieff, conveying both horror and sympathy, has written a wise and sensitive book, even if the wisdom is entangled with puzzlement. In fact, how could it be otherwise? He follows patiently the contradictions of the German predicament: Wessies and Ossies, theoretical brothers no longer, having to share the house, cope with East European and Third World immigrants, and try to find a path between tiptoeing and goose-stepping around the question of national identity.

His reportage from Yugoslavia wisely picks from a surfeit of horror a few telling details that make it new. In a Croatian village, a municipal work crew of women rebuild the house of a man whose parents were killed by the Serbian paramilitaries. “The Serbs are finished,” the man boasts. Three of the women tearfully bow their heads; they are Serbs married to Croatians. The Croatian women stare dispassionately. “Cry, girl, cry,” one says as she takes one of the Serbs’ hands.

All the contradictions are in that scene. Ignatieff lived in Yugoslavia as a child, when his diplomat father was stationed there. The horror was not inevitable, he insists. Nationalism came to the Balkans only in the middle of the last century; the history of Serbian-Croatian hatred is relatively brief.

“It is not how the past dictates the present but how the present manipulates the past,” he writes. “Nothing is inevitable: that is what makes what did happen so tragic.”

In the Ukrainian village where his great-grandparents had their estate, he visits their grave, still tended by the local priest, and locates in himself a bit of the heat that in Yugoslavia became a raging fire. “Graves and nations. Land is sacred because it is where your ancestors lie.”

He sees why “graves and land matter and why the nation matters that protects them both.” He finds the same human need in a wretched colony of Tatars who have returned to their ancestral land in the Crimea after half a century in exile in Central Asia, where they were despised: “Without nationhood people sneer at you on the bus.”

He finds a cheerful nationalism in Kurdistan where, under U.N. protection the Kurds are struggling to build a precarious state; an unexpectedly potent nationalism in Quebec, despite its prosperity, and a perky, doomed nationalism among the Ulster Protestants, who think of themselves as British and whom Ignatieff finds to be utterly Irish.

Few outside writers have troubled to reach for the humanity of Northern Ireland’s majority community. But in his journey among nationalisms, Ignatieff has admirably used a cosmopolitan sensibility to find what is recognizable and human in what, to him and to many of us, seems most strange.