Maybe he should just light up the cigar he has been fondling all morning. Prop master Jack Gelbart, guardian of Cosby's lighter, tosses the thing to his boss. Cosby works on his Cuban cigar, then tosses the lighter back to Gelbart for safekeeping. He plops down on the Huxtable couch, dressed in sweatpants, with a Miles College sweatshirt stretched across his decidedly middle-aged midsection and a baseball cap covering unmistakably graying hair. "Hey, Jay!" he hollers to Jay Sandrich. "Jay, you are not the director I wanted for this show!" Sandrich laughs, because he's the perfect director for this show, the top-of-the-line field marshal (The Mary Tyler Moore Show, Soap) who directed the very first episode and, in fact, every episode of the first two seasons (and most of the third). And while the two banter as if Friday were not the very last taping ever, 21-year-old Malcolm-Jamal Warner, who plays Theo, lopes from Huxtable room to room aiming his palm-size video recorder at colleagues (Warner is a part-time film student at New York University in real life). Keshia Knight Pulliam, 13, who plays Rudy, does her homework at the Huxtable kitchen table. Tempestt Bledsoe, now 18, disappears into her own dressing room, moody as Vanessa, the daughter she plays. Thirty- four-year-old Sabrina LeBeauf, who, as the oldest Huxtable child, Sondra, was off at college by the time the series began, chats with Clarice Taylor, who plays Cliff's mother, Anna. Phylicia Rashad, who plays wife Clair, fingers her prayer beads; 6-year-old Raven-Symone, who plays step-granddaughter Olivia, pirouettes around the living room looking for an audience. (She may have one soon; there's a pint-size pilot in the works for her.) The decision is made: The doorbell will finally chime properly and the fourth wall will be broken. This is how The Cosby Show goes out: with a dingdong that turns into a jazzy send-off to the music of Miles Davis. Rehearsal resumes.

"The ending of the show will probably not affect me for a couple of months. Honestly, I'll wake up one morning and say, 'Yo! This thing is over!'" -MALCOLM-JAMAL WARNER

This, too, is how The Cosby Show ends: a tepid 20th in the season's overall ratings. The show that changed forever the way black families are portrayed on television, the show that paved the way for a rainbow of African-American sensibilities on TV from In Living Color to The Fresh Prince of Bel-Air is getting razzed these days by The Simpsons, which took Cosby characteristics (understanding, respect, family interaction, striving for excellence) and turned them on their heads (belching, insulting, napping, underachieving; in one episode a drowsing Homer nodded off with a copy of Cosby's best-seller Fatherhood splayed on his stomach). The Cosby Show ends minus second-eldest daughter Denise (Lisa Bonet, 24, who left the show in 1987, but who is written into the hour-long farewell episode in a phone call from Singapore, during which she announces that she's pregnant). But the family has gained Pam (Erika Alexander), the Huxtables' inner-city relation, and Olivia (Raven-Symone), Denise's precocious 5-year-old stepdaughter. In all, the series ends a little wistful and soft of punch, these happy few upper-middle-class Huxtables, maligned by addled critics for being too jolly and well adjusted for any family, maligned by addled armchair sociologists for being too prosperous for a realistic black family, and lost amid the noisier, cruder TV families of the '90s, from The Simpsons to Married With Children and even Family Matters. This is what Bill Cosby thinks: "I never could accept how (journalists) could get into the messages that come from films and some TV shows and they never could find any depth with what was going on in the Huxtable house. I find that very offensive." Bill Cosby leaves The Cosby Show without looking back. He's out the door; his private Cessna is waiting to take him anywhere he wants to go. He's developing a series-no airdate yet-for Malcolm-Jamal Warner, about a graduate student who works at a community center. And he's developing a remake of the classic 1950s Groucho Marx TV show You Bet Your Life, a quiz-and-audience- participation series that premieres in syndication in September. After the failure of his last two feature-length comedies, Ghost Dad and Leonard, Part VI, he's cautiously considering a serious movie role. The Cosby Show's 208 episodes have already generated more than $730 million. And in 1991 Forbes magazine named Cosby the second-richest entertainer in America, with a two- year take of $113 million.