THE CREDO OF THE merchant of death, as expressed by Andrew Undershaft, the villain of George Bernard Shaw's "Major Barbara," was clear and unashamed: "to give arms to all men who offer an honest price for them, without respect of persons or principles." It was a philosophy that animated the pioneers of the arms trade, such men as Sir Basil Zabaroff, the Balkan master arms salesman who sold guns and submarines with impartiality to warring Greek and Turk, Alfred Krupp, the "Cannon King" and scion of a family arms dynasty which has left its insignia on the battlefields of Europe for more than two centuries; Alfred Nobel, who produced dynamite in the 19th century and his Peace Prize in the 20th; and Andrew Carnegie, who armored the Russian and American fleets in the 1980s and went on to establish his Endowment for International Peace somewhat later.

It was an era of rampant drive and simple moral confrontation, portrayed by Shaw in the conflict between munitions mogul Undershaft (motto: Unashamed) of Undershaft and Lazarus and his pacifist daughter, Major Barbara of the Salvation Army. The essential nature of the business remains unchanged in our time, as Anthony Sampson's timely new book reminds us. The weapons sales scandals of recent years, in which America's biggest military manufacturers were implicated, do honor to well-established traditions. They are hardly an aberration of modern times.

But there are important respects in which things have changed. In the 19th and early 20th centuries the world's arms traffic was controlled principally by a handful of hard-driving entrepreneurs and the companies which sold their wares to nations and tribes batting each other about in local theaters of war, culminating in that all-encompassing munitions industry scandal known as World War I.

Today, however, there are a host of new actors in the arms transfer business. They have names like the National Security Council, the Bureau of Military-Political Affairs, the Office of International Security Affairs, the Department of Security Assistance Programs, the Bureau of Munitions Control, the Arms Control and Disarmament Agency. They are peopled by anonymous technicians, bureaucrats, lawyers and military officers who serve as the combatants in contemporary arms transfer policy battles.

The government, in other words, has become a major partner in the conduct of the arms sales business. The relationship came to full flower during the Cold War era in the military grant programs fostered under "collective security" treaties between the United States and its non-Communist allies around the globe, substantially raising the worldwide level of weaponry. Correspondingly, the Soviet Union and the industrialized countries of Eastern Europe revieved their own munitions industries to defend the perimeters of Communist hegemony.

The Vietnam War, looked at from this aspect, was a $150 billion arms transfer program which introduced the most advanced products of U.S. military technology to a military theater in Southeast Asia that had been scaled to peasant armies and guerrilla forces.

The Nixon Doctrine, which called for the replacement of American troops with American weaponry and know-how, signalled a new opportunity for the U.S. munitions industry to promote its wares in world markets under the name of national security. Tom Jones, in his capacity as chairman of Northrop, put it very well during a meeting with California bankers late in 1976. Jones, as quoted by Sampson, said that "the interests of a vast number of countries are inextricably linked to the long-term interests of the United States . . . And the need for those countries to defend themselves without sending American troops is all too clear. It is for those reasons that the government and the Congress recognize the responsibility of the United States to allow certain countries around the world to purchase from the United States with their own funds adequate and appropriate defense systerms."

In Iran and in Saudi Arabia, particularly. The Nixon-Kissinger policies shrewdly forged links of interdependence based on the bartering of crude oil for military technology. By fiscal 1974 Iran was purchasing American arms at a rate of $42 billion annually. The corresponding figure for Saudi Arabia was nearly $2 billion. The other big customer that year was Israel with $2.5 billion in U.S. military hardware purchases. U.S. weapons sales abroad reached a record level of $10.5 billion in fiscal 1974.

The figures demonstrate in how substantial a way the United States was collateralizing its foreign policy with weapons sales. This was the context for the arms-selling scandals in which such major U.S. manufacturing concerns as Lockheed, Boeing. Northrop and Grumman figured, as documented by the Senate Multinational Subcommittee investigations upon which Sampson builds much of his narrative.

Where Sampson's analysis falters, in my opinion, is in his failure to allot full credit for the great spurt in American weapons exports during the first half of the '70s to the calculated of Kissinger and the two presidents he counseled. Sampson puts primary stress on the aggressiveness of the arms merchants as the motivating force in the accelerated tempo of weapons sales around the world. At one point he speaks of the "atavistic appeal of arms to the male psyche." The word "weapon," he notes, "was up till the fourteenth century synonymous with penis . . . "

Whatever role may be ascribed to machismo, I would like to have a seen a fuller description and analysis of the critical decision-making by Nixon and Kissinger during the early '70s when the pace of American weapons sales increased tenfold -- growing from $945 million in fiscal 1970 to $10.5 billion four years later.

Those were the decisions which suddenly clogged the Bedouin society of Saudi Arabia and the peasant culture of Iran with squadrons of high-performance jet aircraft, sophisticated electronic intelligence systems, armored battalions and huge colonies of American military technicians. The decision to exchange dependencies, oil for arms, indexed to the dollar, may have been brilliant or calamitous. It will shine in our politics so long as the present regimes stay in power in Riyadh and Teheran. It could prove a disaster if new political leadership arises from the discontent of the populations whose needs remain stinted because of the priorities of military spending.

Some more reporting would have been welcome on the extent to which the arms buying splurge in the Third World has deflected and deformed policies of national development in countries which can ill afford a big weapons culture, such as Turkey, Egypt, some Latin American states, and other countries of Africa and the Near East.

Finally, there is one other aspect of the arms epidemic upon which Sampson touches lightly. It is the proliferation of nuclear weapons technology, the deadliest bazaar of all. President Carter's efforts to hold the line on fast-breeder reactors and uranium reprocessing plants at least show the extent of governmental concern over the unleashing of the plutonium genie -- even though it may be too late for moratoriums on production of the raw material of the bomb. It is a subject which might well be the sequel to Sampson's latest work, which grapples bravely with a subject much too vast for one book.

The Arms Bazaar could not have come along at a more opportune time, before the arms transfer policies of the Carter Administration are set in concrete. Though Sampson generously credits the staff of the Senate Subcommittee on Multinational Corporations, which did much of the investigative spadework on weapons bribery scandals still reverberating through Europe and Japan, he deserves much credit himself for having told the story in a way that is certain to raise public consciousness on this most troubling of international issues.