Adnan Khashoggi, the flamboyant Saudi arms trader who rose to spectacular wealth in the 1970s and 1980s while treating the world to displays of decadence breathtaking even by the standards of that era, died on Tuesday in London. He was 81. His family announced his death in a statement. He had been undergoing treatment for Parkinson’s disease. Mr. Khashoggi had several brushes with the law but was never convicted of a crime. He was involved in many of his era’s highest-profile scandals, including Iran-contra and the Marcos family’s effort to spirit money out of the Philippines. One biography of him was titled “The Richest Man in the World,” and he was often described that way. It was not strictly accurate, but during the early 1980s, his wealth, estimated at $40 billion, placed him in a tiny elite. Mr. Khashoggi was born in the holy city of Mecca on July 25, 1935, one of six children. His father, the court doctor to King Ibn Saud, was of Turkish descent, leaving the family outside the web of connections, obligations and suspicions in the Saudi court. Mr. Khashoggi attended Victoria College in Alexandria, Egypt, a traditional training ground for the Middle Eastern elite, where pupils were caned for using any language other than English. Afterward, he enrolled at what was then Chico State College in California. Barely a year after arriving at Chico State, at 21, he brokered his first major deal, the sale of $3 million worth of trucks to Egypt. His commission was $150,000. He never returned for his college degree. In 1961, Mr. Khashoggi married a 20-year-old Englishwoman, Sandra Daly, who took the name Soraya. They had four sons and a daughter, Nabila, for whom he named his storied yacht. They divorced in 1974. Five years later, a judge ordered Mr. Khashoggi to pay Soraya $875 million, the largest-ever divorce settlement at the time. Mr. Khashoggi began traveling with his second wife, an Italian named Laura Biancolini, when she was 17. Like Soraya, she converted to Islam after their marriage and took a new name, Lamia. They had a son, Ali. Later Mr. Khashoggi took an Iranian-born wife, Shahpari Azam Zanganeh. A high-living Middle East power broker with once-limitless wealth, Mr. Khashoggi was among the last of his breed. He thrived in an era of gaudy excess and came to epitomize it.