SIR RUDOLF BING, the controversial general manager of New York's Metropolitan Opera for 22 years, has always been known for his steely professional composure and "arrogance." In these new memoirs, a curiously sketchy but entertaining set of "variations" on themes and incidents from the bestselling 5000 Nights at the Opera, Bing bridles at the notion that the Met was an "unhappy house" under his tenure but seems to rather relish his dictatorial image. When Julius Rudel of the New York City Opera asked him in 1973 to play an important silent part in Henze's The Young Lord because the role required someone "distinguished-looking, elegant and arrogant," Bing writes that he found the offer "an amusing idea" and immediately asked for a libretto. On opening night, he received a telegram from Birgit Nilsson which read, "Even if your role is speechless, I'm sure you will have the last word."

According to director Garson Kanin in his marvelously understated and affectionate introduction to this book, Bing was indeed a man of few words who always had the last one. From 1950-72 Bing made himself almost invisible, appearing during a production only when he was needed "as if summoned by unseen, unknown forces, to deal with the crisis at hand." With his surgical managerial precision, his understanding that opera includes theater as well as music, and his uncanny instinct for matching the right singers with the right seasons, the right conductors with the right scores, he transformed a mediocre Met into the world's most formidable and exciting opera house. A glance at the seemingly endless appendix listing the stars Bing brought to the Met-- Caball,e, Callas, Flagstad, Tebaldi, Domingo, Bjoerling, Pavarotti, Siepi, Karajan, Bernstein--gives a startling indication of his achievement.

When Kanin was hired to direct Strauss' Die Fledermaus during Bing's first season, he observed the "Bing method of administration" first-hand. Conductor Fritz Reiner, whose reputation for tyranny and aloofness was already safely in place, refused to go along with Kanin's idea of having the singers lie on enormous pillows during the orgy scene. "You will be standing and facing the audience and keeping your eyes on me," said Reiner to the singers, adding to Kanin, "Singers cannot sing lying down. Sometimes not even standing up." Suddenly Bing materialized out of nowhere, "raised his eyebrows quizically" at both men to hear their arguments, said "thank you, gentlemen," and disappeared. Later that day, Kanin noticed Reiner being quietly ushered out the door by Bing's assistant, to be replaced by Eugene Ormandy, who began the first rehersal with, "And for heaven's sake, don't look at me all the time. . . . Let us all try to carry out the director's conception. If he wants you to sing standing on your head, let us try it."

Reading A Knight at the Opera is like witnessing the Bing method on the printed page. Whereas 5000 Nights at the Opera was chatty, expansive and swaggering, this work, published on the occasion of Bing's 80th birthday, is spare and underplayed. Bing's method consists largely of listing famous names, reproducing dramatic letters, chopping at enemies with brief karate strokes, and recalling recently departed friends in brief, touching elegies. His famous firing of Maria Callas, for example, so vividly depicted in the earlier memoirs, is embellished here with a series of letters documenting his frustrated attempts to entice Callas back to the Met in the late 1960s. Bing's terse commentary on this correspondence is limited to the opinion that the temperamental and "tragic" Callas finally "ended her life," finding it "unbearable to sink from the top of the world" to "total loneliness."

Bing's own loneliness, which he characterizes as "desperate," is briefly but chillingly depicted in a section describing the paralyzing stroke recently suffered by his wife of 52 years. In 5000 Nights, Bing characterized himself as "a rather melancholy person"; now, with his lifelong companion unable to speak to him anymore and his friends dying around him, he writes that "never again" has become his "leitmotiv."

In spite of this somber context, Bing's irascible, hard- nosed humor is still delightfully in evidence. When trying to account for Callas' triumph in Japan during her final tour when all her Western concerts were "disasters," he finally shrugs, "the Japanese also like raw fish"; and when recounting his 1973 appointment to the faculty of Brooklyn College, he remarks, "having flunked every course in school, I got the job of 'Distinguished Professor.'".

Bing also offers serious, seasoned arguments on a wide variety of operatic topics. Unapologetically autocratic as ever, he states that financial and musical questions are inextricably connected and that "only ONE person must have the final power" in a house. In the shadow of Reagan budget cuts, he also argues that "opera simply cannot exist without substantial subsidy."

It is unfortunate to have to report that despite its value as a document, A Knight at the Opera is weakened by some embarrassingly empty and ungainly sentences: "After the first ten minutes one feels as if one had known each other all one's life and even after a year's absence one feels as if one had met only yesterday." One wonders what happened to one's copy editor.

The general reader should also be warned that the texture of this book is rather thin. A Knight at the Opera is a book for committed opera buffs, especially those who have already sampled 5000 Nights and are eager for an encore. Reading it is like walking in on an elegant, important conversation that has been in progress for a long time and is about to end.y