Question: Was Welcome Back, Kotter based on a real-life teacher? I always thought it was. Thank you. — Terri K., Quantico, Va.

Televisionary: Nope, but the show was inspired by star Gabe Kaplan's stand-up comedy routines, which in turn drew from the comic's own past as a juvenile delinquent and academic underachiever. Not that Kaplan wasn't bright; he just didn't feel like doing his assignments at Brooklyn's Erasmus Hall, which ranked him a four out of five in its one-to-five intelligence rating system. "I was always in the fours, next to the dumbest," he told TV Guide in 1976. "Actually, the fours were the dumbest because the fives were the troublemakers."

Kaplan eventually dropped out of high school altogether, so there was no hint of any future success, never mind the fame and fortune that came when he played a teacher who returns to his alma mater to teach remedial students in the hit ABC comedy, which ran from September 1975 to August 1979. To hear Kaplan tell it, though, the system and the way the adults treated him were partly to blame for his early lack of motivation. "Once you tell a kid he's a four or a five, he stops trying," Kaplan said, sounding much like his teen-saving character, "though inwardly I secretly knew I was going to amount to something."

He amounted indeed, though early in the show's development, its future looked about as promising as Kaplan's academic career. First off, Executive Producer James Komack (The Courtship of Eddie's Father, Chico and the Man) hated the concept and had little enthusiasm for Kaplan's comedy. So he walked out on the show three times before warming to both and deciding to stay. Even then, however, his star presented a challenge. "I thought Gabe was the strangest man I had ever come across," he said. "As Gabe will tell you, he's emotionally a difficult and unusual person. Sure, he talks nonstop, but he's not communicating — he's performing. Conditioned to be on his guard, he's unable to trust people totally. But as he gets further into the business and gets more trust and confidence in his audiences, he will slowly reveal more of himself — which is a charming, warm man with a funny sense of humor."

Many of the show's critics never got to that point. A group of station managers hated the wiseacre Sweathogs (John Travolta, Robert Hegyes, Lawrence-Hilton Jacobs, Ron Palillo) and, after viewing only the pilot, said the show was "glorifying hoodlums." (One wonders how they would have received The Sopranos.) The National Education Association tried to force the show to accept an adviser in order to "protect the image of schoolteachers." And Boston's ABC affiliate initially banned the show, saying it "advocated the kind of bad attitudes that are not proper behavior in the classroom."

All of which should have upset Mr. Kotter himself, but Kaplan took it in stride. "[B]eing banned in Boston is funnier than anything we're doing on the show!" he said. "It puts us in the same status as Ulysses, Lady Chatterly's Lover and Deep Throat!" And when he went on The Tonight Show, he let the educators have it, too: "Would you believe a technical adviser on Sanford and Son to protect the image of junk dealers?"

None of that mattered, of course, to Travolta, whose career quickly eclipsed anyone else's on the show (particularly after the 1977 release of Saturday Night Fever). After just one season, he was already a sensation, second only to Happy Days's Henry Winkler. With 7,500 pieces of fan mail coming in a week, he was featured on posters and records and was leaning heavily on Scientology to maintain his sanity. However, even faith and philosophy couldn't keep his personal life sane.

Whenever Travolta returned to his childhood home in Englewood, N.J., he snuck in, unannounced, in the middle of the night. "It's because of my mother," he explained. "Both my folks are enjoying my success more than I ever could, and that's great. But if I tell her I'm coming, she tells the whole town. And the next thing you know, all these strangers are prowling around the place, peeking at us and tearing out chunks of the house as souvenirs."

As far as his co-stars went, they alternately enjoyed and suffered through the effects of their fame, too. Jacobs had to yell at five girls who insisted he invite them into his place in the wee hours of morning, for example, and Palillo was forced to do Arnold Horseshack's trademark laugh for strangers who approached him in restaurants. Even Palillo's fan mail left something to be desired. One girl asked him to become the father of her child. "And you won't even have to do anything about it," she added. "I'm already pregnant." A schoolteacher who was sick of her students imitating the famous laugh (which Palillo invented on the spot at his audition to differentiate himself from the competition) wrote: "I sometimes wish your show had never come on the air."

All of which may have contributed to the prescience Palillo demonstrated early in the show's run, when the ever-optimistic Hegyes called, almost breathless, to tell him, "Ron, we can be the new Beatles!" The man who was Horseshack replied: "Bobby, we can't even be the new Monkees."

And with the exception of Travolta's blockbuster career, he was right.