TWO YEARS AGO candidate Ronald Reagan publicly

doubted that "it's any of our business" who gets nuclear weapons or how.

There is no law that a candidate must know what he's talking about; but this was, as the authors of this book show, a particularly egregious outburst of glibness, even for Mr. Reagan. It is their view, well supported here, that only a policy of resolute "denial" of the means of nuclear weapons manufacturing offers hope against wild proliferation.

Clearly, the nuclear nonproliferation treaty of 1968 has failed, at least in part. It rested on the assumption that "peaceful" nuclear technology could be transferred without the risk of military use. The Indian "peaceful" nuclear explosion of 1974 knocked that credulous fiction into a cocked hat. Moreover, the inspection regime run by the International Atomic Energy Agency is ineffective. Inspectees largely set the locales and terms of inspection. Iraq, for instance, has admitted inspection teams consisting only of Russians, Hungarians and Frenchmen. This would arouse the gravest suspicion in itself, were it not for the evidence presented by Weissman and Krosney that the Soviet Union has been somewhat more cautious and careful in the distribution of nuclear technology and weapons-grade fuel than, say, our friends France and Italy.

Actually the comprehensive nature of this book makes its title a bit misleading. The authors indeed focus, in fascinating if sometimes confusing detail, on the effort secretly launched a decade ago by Pakistan's late Ali Bhutto and now continued by Iraq's Saddam Hussein to develop an "Islamic" nuclear weapon.

But this is only one aspect of the complex and alarming traffic in dangerous nuclear technology, open and hidden, monitored and unmonitored, much of it, as indicated above, a West European responsibility.

In most ways, and not only in regard to the Pakistani and Iraqi sneak plays, the story is very murky. Nearly every "fact" about nuclear weapons development, not only in the Islamic countries but in India and Israel, is to a degree inferential. Israel may have the Bomb and, according to Weissman and Krosney, actually leaked a story to that effect in the desperate hours of the 1973 war, later denying it. Yet it is Israel's now-familiar declared policy "not to be the first to introduce nuclear weapons into the Middle East"; and at its very clearest Israel's is a policy of "deliberate ambiguity."

India, the only third-world nation to have openly tested a nuclear explosive device, may have the capacity to make nuclear weapons, or may already have them but denies that it has. India's nuclear future is undoubtedly contingent to some degree upon what Pakistan may do with the array of technologies it has cleverly bootlegged into the subcontinent; and that in turn may depend on such variables as U.S. willingness to protect Pakistan in other ways.

Before the Israelis bombed out Iraq's Osirak reactor last summer, its dictator Hussein was less explicit about his quest for an "Islamic" bomb than he became thereafter. But among those who study such matters, few doubt that the project is on Iraq's nuclear agenda--or that Libyan money is involved, as it is and has been in Pakistan's case also. Incidentally, Israel was not alone in fretting about Iraq's plans, or in querying its eager supplier France about the high technology being sold to the Baghdad regime. (The French-Iraqi agreement promised six "loads" of uranium-aluminum alloy fel, including in all some 13 kilograms of weapons-grade fuel--enough, the authors say, to build from four to nine Hiroshima- scale weapons.)

Israel is not alone, perhaps, in working by means fair or foul to thwart the Iraqi bomb. Well before Osirak was bombed (and the Iranians were the first to attack nuclear installations in Iraq) a series of mysterious incidents had plagued Iraq's nuclear program. Reactor cores manufactured in France, awaiting shipment from a seaside warehouse in La Seyne-sur-Mer, were blown up in April 1979. A bit over a year later, Dr. Yahya el-Meshad, an Egyptian nuclear engineer working for the Iraqis, was bludgeoned and left to die in his room at the Hotel Meridien in Paris. The Israelis were suspected, as usual, although this cruel and clumsy assassination seemed to most observers uncharacteristic of Israeli agents.

Of such intrigues, so intricate as to be hard to follow at times, The Islamic Bomb is full. But for readers who care for more than sleuthing, and who wonder about the larger implications, Weissman and Krosney have other things to say.

If it is true, as they argue, that the nonproliferation treaty has failed, it remains imperative to find legal and direct diplomatic ways to restrain proliferation. For if diplomacy fails, the prospect is that those directly threatened by regional bombs will turn to terrorism, sabotage and even open attack as a remedy--as the Israelis did last year in bombing Osirak, no doubt to well-suppressed applause in unlikely quarters. In the long run this dog- eat-dog struggle, without rules, cannot arrest and may even assure proliferation. Already the Pakistanis have emplaced anti-aircraft rockets at their nuclear sites; and already, in Israel, there are respected strategists calling for an overt policy of nuclear "deterrence."

Of course a principal force propelling unpoliced sales of nuclear fuel and technology is the oil thirst. The authors suggest that France's profitable deal with Iraq remains unpublished because certain provisions of the agreement make the swap of nuclear materials for an assured oil supply explicit. In 1980, France bought no less than $5 billion worth of imports, mostly oil, from Iraq. This connection explains, of course, why the Carter administration anti-proliferation policies, while enlightened and strict in principle, seemed patronizing and unrealistic to nations that depend on imported oil altogether.

The Islamic Bomb is an important book, and Weissman and Krosney are diligent reporters. It is the more unfortunate, therefore, that their writing is marred by so many of the breezy techniques of television reporting. They find it hard to state or document a fact without a tedious recital of where, when, how and from whom they obtained it. "Over drinks at the such-and-such hotel . . ." is the kind of scene-setting phrase they cannot resist and with which they maddeningly preface almost every revelation. But readers patient enough to wade through this script-like journalism, with its abrupt and confusing shifts of scene and locale, will be well rewarded. The book is a goldmine of information, apparently factual, about what is or should be our No. 1 worry. President Reagan should read it. If he does, he will see why nuclear proliferation is everybody's business and especially ours--as every postwar American president has acknowledged.y