IF LIVING WELL is the best revenge, Adnan Khashoggi, fabled Saudi middleman and fixer, must feel smug. The richest man in the world, Khashoggi has a net worth of $4 billion and a monthly American Express bill in excess of $1 million. He has 12 elegant homes, all fully staffed, in places such as Rome, Paris, Monte Carlo, Kenya, New York, and of course Riyadh. His private air force includes a 727 and a DC8, each outfitted to provide a magic carpet ride for an airborne harem. His 280-foot yacht the Nabila, one-third the size of the luxury liner United States, has its own disco, movie theater, and helicopter pad, and functions as a floating pleasure palace where Khashoggi entertains beauties like Cheryl Tiegs and Racquel Welch; fellow powerbrokers like Henry Kissinger and Lee Iacocca; and princes like Juan Carlos of Spain and Constantine of Greece, as well as the men who make up the royal house of Saud.

This is what Khashoggi owns and how he lives, as Ronald Kessler tells us in often cloying detail in The Richest Man in the World. The question of who exactly this mysterious Arab is proves to be more illusive. The son of the court physician to Saudi King Abdul-Aziz, who in his lifetime had 43 sons who would control the Islamic monarchy he proclaimed in 1932, Khashoggi came to the United States in 1952 at the age of 17, enrolling somewhat improbably at California's Chico State College. He was not a brilliant student, but he was, as John D. Rockefeller once said of himself, born to be rich.

When his father sent him $10,000 to buy a car to drive around the barren plain of Chico, Khashoggi instead invested the money in a truck which he then leased to a company back home in Saudi Arabia. It was the beginning of an economic life based on the insight which eventually made him rich beyond comprehension: that oil would transform what had once seemed the blighted bedouin kingdom of Abdul-Aziz into an El Dorado of wealth and make its ruling family major players in the postwar world. Khashoggi knew that he could never be a prince; but he could be an attendant lord to princes -- the ultimate intermediary, the alert factotum who greased the skids and made sure that the immense wealth flooding the coffers of the house of Saud got spent -- not wisely, perhaps, but well.

Khashoggi took to this role like a camel takes to sand. By the 1960s he had seen that the real money was to be made in military hardware. The heirs of Abdul-Aziz were presiding over the kingdom's military build-up, which Khashoggi helped broker. He earned over $100 million from Raytheon on sales of $1.5 billion to the Saudis over a 10-year period; $109 million from Lockheed; and $184 million from Northrup on sales of $4.2 billion for F-5 fighter planes. By the 1970s he was prince of the Saudi military-industrial complex.

Kessler never really gets inside his subject -- Khashoggi is either too inscrutable or too shallow for that -- but he is a good journalist and puts together a vivid picture in the early part of this book of the Saudis' endless greed and cupidity, which is exceeded only by the cowardice and greed of U.S. corporate officials determined to arm this tiny kingdom to the teeth. Khashoggi's genius was to know how to play each side off against the other, and how to take advantage of the misunderstandings and faux pas in cross-cultural negotiations. But after the first few chapters, Kessler turns his attention to Khashoggi's lifestyle into numbing details about this modern sheik's airplanes, his homes, and his women. The Richest Man in the World concludes with an interminable account of Khashoggi's divorce from his British-born wife Soraya, whom he'd married at the beginning of his meteoric rise. KESSLER's insights into Khashoggi's career could have been a sound magazine piece or newspaper series. But in book form they have the feel of a research file rather than biography. The author seems always to be huffing and puffing to bulk out the contents of the book. Subsidiary figures who play a brief role and then disappear are always introduced by a digressive portrait that tells us far more than we need or want to know about them. We are told that Thomas V. Jones, president of Northrop, has a high forehead, black glasses, and big ears. Attorney Marvin Mitchelson, who handled Soraya Khashoggi's divorce, is accorded several paragraphs describing the furnishings of his office and his palimony clients. It is not just a tedious attempt to inject human interest into the flagging narrative, but also something of an authorial tic, as we discover when Kessler mentions a Khashoggi investment in Salt Lake City and can't keep from adding this modifier: "where Brigham Young hid his flock from persecution on July 24, 1847."

At the end of The Richest Man in the World, the reader feels as if he has been forced to watch a mega-episode of Lifestyles of the Rich and Famous. Kessler overestimates the interest golden bathroom fixtures and Impressionist canvasses on the walls of very long yachts have for us. Niarchos and Onassis had them with their modest $1 billion net worths. Khashoggi with his $4 billion doesn't have anything much different from what they had; he just has more of it. It may be that Dylan Thomas' dictum about death holds for chronicles of rich men as well: after the first one all the others are the same.

Peter Collier is the co-author, with David Horowitz, of "The Rockefellers: An American Dynasty" and "The Kennedys: An American Dream."