That’s the narrative line in Walter Isaacson’s new book, Kissinger: A Biography (893 pages. Simon & Schuster. $30). In Isaacson’s steady stream of ironies, Kissinger’s sheer brilliance-his gift for conceptualization, his intuitive understanding of power and his skill as a negotiator-is matched by compulsive egotism, sycophancy and duplicity. Isaacson, an assistant managing editor of Time magazine, was coauthor, with NEWSWEEK’S Evan Thomas, of an earlier book on postwar American statesmanship, “The Wise Men.” His biography of Kissinger manages to have it both ways: friendly and unflinching. He dishes plenty of dirt about Kissinger’s personal weaknesses, but he also pays tribute to the clarity of his vision and the deftness of his diplomacy.

Isaacson’s principal complaint is that Kissinger practiced realpolitik at the expense of morality, never grasping that America’s strength is based in part on doing the right thing. “The structure of peace that Kissinger designed places him with Henry Stimson, George Marshall, and Dean Acheson atop the pantheon of modern American statesmen,” he writes. “But Kissinger never had an instinctive feel for American values and mores.”

Kissinger never pretended to be a moralist. He was this century’s greatest diplomatic technician, a hard-eyed realist who used balance-of-power dynamics to shore up his adopted country when its idealism was lost in the wreckage of Vietnam. He and Nixon produced grand designs–the breakthrough to China, detente with the Soviet Union, shuttle diplomacy in the Middle East-that helped to steer the United States through the shoals of self-doubt toward ultimate victory in the cold war.

Born into an Orthodox Jewish family in Bavaria, young Heinz developed “that odd mixture of ego and insecurity that can come from growing up smart yet persecuted,” Isaacson writes. After his family moved to New York City in 1938, Kissinger displayed the immigrant’s eagerness to please. He attached himself to a series of patrons: an army officer, a Harvard professor, then Nelson Rockefeller and Nixon. He could be amazingly obsequious. In 1971, he sent Nixon a mash note that read: “Your serenity during crises, your steadfastness under pressure, have been all that have prevented the triumph of mass hysteria. It has been an inspiration to serve. As always, H.” When Kissinger met Pat Nixon for the first time, he praised her husband lavishly. “Haven’t you seen through him yet?” she asked.

Well, yes, he had. Behind Nixon’s back, Kissinger could be deeply contemptuous of the president. He would call Nixon “our drunken friend,” a “basket case” or “the meatball mind.” Nixon had no illusions. Once, after a string of temper tantrums from Kissinger, the president “said that perhaps he would have to fire Kissinger if he did not agree to seek psychological help,” Isaacson writes. As he left office, Nixon said, “There are times when Henry has to be kicked in the nuts. Because sometimes Henry starts to think he’s president. But at other times you have to pet Henry and treat him like a child.”

One of the most improbable parts of the Kissinger persona was his self-proclaimed status as a swinger. In the years before his 1974 marriage to Nancy Maginnes, he dated a conspicuous string of actresses, including Jill St. John, Samantha Eggar, Shirley MacLaine, Marlo Thomas, Candice Bergen and Liv Ullmann. “Power is the ultimate aphrodisiac” was one of his most famous sayings. It may explain what women saw in him, but what did he want from them? Perhaps celebrity. “The dirty little secret about Kissinger’s relationship with women was that there was no dirty little secret,” writes Isaacson. “He liked to go out with them, but not home with them.”

Fifteen years after leaving office, Kissinger is still working hard to keep himself in the limelight, as a big-ticket speaker, a commentator for newspapers, television and magazines (including this one), and an international consultant in his own firm. “The secretive world of Kissinger Associates,” Isaacson writes, “involved a lucrative blend of strategic advice, foreign affairs insight, good connections, some door-opening, and the cachet that came from one of the world’s most marketable names.” In a good year, Kissinger earns up to $8 million. He is only one of eight living former secretaries of state. But in Isaacson’s view, his “mixture of brilliance and abrasiveness, ego and insecurity, charm and furtiveness, humor and ambition had made him, for better and for worse, one of the premier stars of his era.” In glittering semiretirement, Kissinger has become a monument to himself.