In a scorched and muddy barbed-wire enclosure at Sa Kaeo, Thailand, where some 31,000 Cambodian refugees had been herded in October 1979 to die at the rate of 20 or 30 a day, the commercial instinct was alive and well.

"At the height of the debacle," writes Barry Wain, "several coachloads of camera-toting tourists arrived . . . to snap the walking scarecrows . . . A Thai travel agency was thoughtfully running special day tourists from Bangkok: come and see the Kampuchean refugees before they all fall down."

Wain's account of the catastrophic human dislocations Indochina has suffered since 1975, of which this vignette is typical, cannot be read without indignation. Surely, some special torment in Dante's inferno is reserved for exploiters of human misery.

And yet, this easy armchair indignation is falsified by one's sense of honesty. We confront, here, something deeper, older and more complex than callousness. In his great poem "Musee des Beaux Arts," W.H. Auden glimpsed it when he observed that the Old Masters--he was meditating on Breughel's "Icarus"--were never wrong about human suffering. It somehow invites indifference.

As some will immediately protest, the lot of Indochina's "boat people" has been an international scandal. And so it has been, in one sense. Every partisan has found in it some vindication of his preconceptions about the generations-long revolutionary upheaval in Southeast Asia.

Wain offers evidence for the vindication of most prejudices--whether one views the calamity as a belated consequence of U.S. intervention (for the denuding of arable land by endless bombardment and defoliation did accentuate famine); or whether one views it, as more nearly it was, as a consequence of the cynicism, avarice and ideology of the Vietnamese government (which, when the great eruption of people began in 1978, profited from it to a degree that made the "export" of refugees an earner of foreign exchange to rival coal).

Wain, an Australian, covered the catastrophe for The Asian Wall Street Journal. He is a reporter, and in this book an excellent one, not a moralist. But in moral terms the story speaks for itself.

There had been a preliminary flight from South Vietnam during and after the fall of Saigon to Communist forces in April 1975. Most of those who took flight then were true political refugees, people whose former affiliations with the French or Americans exposed them to real danger. A quiet interlude followed. The North Vietnamese conquerors, with relatively clement policies, attempted to consolidate their control slowly by "re-education" rather than brute force and, for a time, tolerated the "bourgeois" anomalies of the South.

But as the new regime's policies took hold (for instance, the March 1978 decree abolishing "all trade and business operations of bourgeois tradesmen," occasioning the end of more than 30,000 small businesses, especially in Saigon's ethnic Chinese precinct of Cholon), the real outpouring began.

It was also spurred by famine, despair, bad weather, official policy (the same calculated persecution of ethnic Chinese), and soon by the armed clash between China and Vietnam on the one hand and Vietnam and Pol Pot's murderous Cambodian regime on the other. The latter campaign trapped vast numbers of ethnic Kampucheans between the Vietnamese invaders and the fleeing Khmer Rouge.

The human currents were soon flowing in every direction--Lao hill tribesmen driven to Thailand; ethnic Kampucheans westward to the same thronged country; ethnic Chinese and Vietnamese, by sea and often with official extortion, to fetid camps in Hong Kong, Malaysia, Indonesia and the Philippines as places of tenuous first refuge. Wain estimates that some 1.7 million people, all told, were dislocated in the four-year period. And the slow assimilative resources of the world fell far behind, creating alarm, resentment and even resistance by force. About 30,000 people, Wain also believes, died at sea.

The reception of survivors was a mixed story of humanitarian response (e.g., by crowded Hong Kong); of bureaucratic torpor and understaffing at the U.N. High Commission on Refugees and its outposts; of anxiety in the overcrowded countries of first resort lest emptier nations prepared to receive refugees for permanent resettlement (chiefly, the United States, Canada, Australia and France) not absorb the outflow rapidly enough. And the confusion was complicated by the tangle of ethnic, national and religious tensions that mark Southeast Asia.

There was sufficient blame and bungling to go around. But Wain's most impatient indictment focuses on the Vietnamese government. With the collusion, often, of overseas Chinese middlemen, the Vietnamese government slyly profited from this miserable commerce. It cynically committed hordes of helpless people to the sea in undersupplied and derelict boats and ships, counting profits more carefully than human cost.

When, for instance, the captain and officers of the ship Huey Fong were tried in Hong Kong in June 1979 it was discovered that its 1,700 adult passengers had paid an average of 12 taels of gold (about $250 per tael) for passage. Hanoi's haul from this uncertain voyage alone was about $4 million, not counting confiscated property left behind.

Wain's basic point is that the world is no more prepared today than ever for dislocations on such a scale (and the refugee problem in Africa is thought to dwarf that of Indochina). The standard definitions of who is, or isn't, a true refugee were too narrow. Traditionally, political oppression has been emphasized in international law. But those who fled Indochina by land or by sea in 1978-79 were also fleeing famine, ethnic hostility and hostile government policies that fell somewhat short of specific political persecution.

The 20th century has been an era of almost unexampled dislocation--more so, perhaps, than any age since the murderous religious warfare in the 16th century. Yet Wain's account shows that the realization hasn't quite sunk in. Despite the valiant efforts of a few, most of this forced migration finds the world hostile and unprepared--or, worse, indifferent.