AN UNEXPECTED disclosure in Jacob Goodwin's Brotherhood of Arms is that the founder of General Dynamics Corporation may have served as the model for the dauntlessly cheerful ("What? Me worry?") cartoon character Alfred E. Neuman. Such corporate optimism would come in handy today.

Defense contractors are hardly pathetic waifs one need shed too many tears over, and lately they have not been overwhelmed with sympathy or even understanding. Nevertheless, like it or not, they are as essential a part of U.S. military capability as the Air Force or the Marine Corps.

At the end of World War II, outnumbered by the Soviets and unwilling to match them in numbers of troops, this country embarked on a policy of defense through nuclear deterrence and technological superiority. The need thus generated to buy sophisticated weapons spawned companies to make and sell them, enterprises that now are the most confusingly regulated industry in the United States. Their engineers and designers have dreamed up and built some remarkably capable machines -- as well as some others. And unless someone besides Admiral Hyman Rickover would like to nationalize the defense plants -- hoping perhaps for the delights of public management demonstrated daily by the U.S. Postal Service -- they are a crucial part of the defense team, albeit one that needs plenty of skeptical watching.

Until now, three worthwhile books on how U.S. weapons are bought have appeared: the 1974 classic Arming America by J. Ronald Fox of Harvard Business School; Jacques Gansler's more recent The Defense Industry; and Norman R. Augustine's collection of Swiftian wit published under the title Augustine's Laws. All three authors are former Pentagon officials, and their works presuppose either some familiarity with the system or a diligently attentive reader.

Goodwin's Brotherhood of Arms is less profound, but far more accessible to the responsible citizen who does not know whether a DIVAD belongs in a tool box or bolted to a deck, or why some missiles cruise and others don't. Goodwin, a reporter for some of the most respected journals of the defense press, has remembered how to write for non-experts with clarity and humor, and how to explain without skipping steps. With instructive anecdotes and personality vignettes he allows a peek into that part of the U.S. defense establishment that this country (probably wisely) has chosen to keep partly in the private sector -- the arms industry -- and he conveys the flavor of the big-time military-industrial culture. He has managed to be balanced without being boring. His is not the last book to read on the subject, but it is not a bad choice for the first.

Brotherhood of Arms is the history of a defense contractor: the John P. Holland Torpedo Boat Company, founded by a tenacious Irish immigrant submarine-inventor in 1893, and better known recently as the General Dynamics Corporation. The choice of subject is perfect to illustrate how the current defense industry came to be. Supplying United States armed forces through one 20th-century war after another, General Dynamics grew into the largest U.S. defense contractor (recently it slipped to number three). GD remains unique in the breadth of its arsenal. Unlike most of its competitors, General Dynamics sells centerpiece weapons across the military spectrum: to the Army (the M-1 tank), the Navy (Trident and attack nuclear submarines), and the Air Force (the F-16 fighter), with cruise missiles for anyone who will buy.

In recent months GD has also been reviled more than any other company, and its executives have been brought low. Fifteen years ago its incoming Chairman, David S. Lewis, could imperiously dictate that the company shift its headquarters from New York to St. Louis so he would not have to move; this spring he retired in the face of clamor that he be personally branded with the scarlet letter of debarment from government contracting.

For the reader who simply enjoys a good corporate potboiler, there are plenty of character parts here:

Lee Iacocca, who decided to ditch Chrysler's profitable tank company after telling its briefers, "I don't know what the hell you're talking about."

Henry Crown, who began peddling matches door to door in Chicago, and eventually bought control of General Dynamics.

"Mr. Mac," the founder of current number-one defense contractor McDonnell Douglas Corporation, figuring on his slide rule how many bottles of liquor to order for a party.

Panagiotis Takis Veliotis, GD's fugitive vice president, now safe from extradition in Athens, who hurls cassette-tape thunderbolts back at his former colleagues with cunning and fury straight out of Sophocles.

Goodwin's book is not fluff, however. For all the tales, and an occasional lapse into choppy reporting in the manner of news columns, Goodwin effectively dispels the fantasy that the high cost of defense all comes from cheating or stupidity -- as if there were a line-item in the Pentagon budget labeled "waste, fraud and abuse," if only someone could find it.

It would be simpler and more satisfying, Goodwin concedes, "to believe in a nefarious network of greedy, influence-peddling arms manufacturers, incompetent and tradition- bound military officers, self-serving political appointees in the Pentagon, and corruptible members of Congress." Actuality, he demonstrates, is more complex -- but also more captivating. The cast of Brotherhood of Arms is generously peopled with exemplars of all those groups. But its stage is ample enough to display also some of the competent, honest, patriotic and wholly human individuals who toil for their country as well as themselves in the military- industrial complex.

GOODWIN's colorful case history of General Dynamics illustrates some other truths that seldom get much attention, such as the precarious economic vulnerability of the defense companies themselves. "Even the most diversified defense contractor has only four possible customers: the Army, Navy, Air Force, and Marine Corps" and "Few defense contractors can antagonize their customers and prosper." That condition is as old as the industry. In 1927, Goodwin recalls, to work off "excess profits" GD's aviation predecessor, Consolidated Aircraft, was forced to sell 50 new airplanes to the army for $1 each, and paid no dividends for the next nine years. Today's weapons makers suffer, with silence and contrition that would otherwise be inexplicable, an apparent judgment by the incumbent secretary of defense that the way to sell his big budgets is not to appoint officials who can manage his department, but rather to beat up on defense contractors.

Goodwin demonstrates that the weapons- buying process owes more to human nature than to deviltry. He says too little, however, about what could be done to produce weapons more quickly and cheaply. For example:

Defense procurement is overpoliticized. Programs are spread among congressional districts, and stretched out to keep jobs for constituents. It is difficult, in fact, to build aircraft as slowly as this country has learned to do.

Competition needs to be nourished, even if to do so costs more in the short run. Look at the fire-sale cuts in the price of GD's F-16 that have suddenly become possible now that it has to fend off Northrop's upstart F-20.

The military services should be forced to treat cost as a limiting factor in their weapons designs, intead of just seeking high performance. Unfortunately, they have every reason to believe that if they lower unit costs, Congress will not increase the number of items purchased.

Contractors would do better with more leeway in design, instead of trying to meet blueprints drawn up by committees of colonels. Brotherhood of Arms documents the Pentagon's reluctance to adopt one of the revolutionary weapons of this generation, the cruise missile, because it threatened existing ways of doing things. The example is not unique.

Modern weapons are here to stay, and they are likely to remain costly as long as they stay modern. "Designing a new weapon is not like designing a better toaster," Goodwin observes, and recalls the comment of a British admiral after the 1862 battle of the ironclads at Hampton Roads: "Henceforth the man who goes into action in a wooden ship is a fool, and the man who sends him there is a scoundrel." Few of the critics of modern weapons watch the evening news on black-and-white television sets.

No time in our lifetimes is defense going to become cheap -- nor any less necessary than Mr. Caspar Weinberger rightly says it is. But it can be carried on more sensibly if intelligent citizens learn enough to see past the hysteria about hammers and toilet seats and to understand the way this imperfect and fascinating system really works. Brotherhood of Arms is an accurate and entertaining step toward that public education.