The day comedian Redd Foxx first made the cover of The Jet magazine, he interrupted the filming of his television show to read every morsel. "I have been trying to get on the cover of The Jet for 20 years," Foxx told his anxious producers. "I have made it and I am going to read every word. This doesn't mean anything to you but this is our Bible."

"The Holy Writ of people of African descent," is what its executive editor prefers. Whatever -- Bible, eyesore, status symbol, The Jet has been a mirror of much of black America for the last 30 years. Its mix of telling it like it is, and sometimes isn't, sells 700,000 copies a week and last year earned $29 million in revenues, making The Jet the 49th-largest magazine in America, according to Folio Magazine.

A steady digest of black accomplishments, misdeeds, trivia, history, photographs, society events and sob and freak stories make each 5-by-7 inch issue a snapshot of modern black life. From "Sister Is Surrogate Mom For Transsexual Mother" to "Birmingham's Black Mayor Sees Many Positive Points," readers in black America can keep in touch through the magazine. They will find out who died, who got promoted, who is suing whom, who shot whom, what famous black person was born when, who has the No. 1 record, what the latest fashions are, who was at what party, who said what, and which black college won what game.

The Jet, as it's known to its fans, marks its 30th anniversary this month. Its lively combination of service and slapstick journalism has become a cultural institution. Sandwiched in between serious news on black issues are stories such as "Stars with Clean Heads," from 1980: "Slick Bean! Skin Head! Grape Nut! Who'd have imagined those tormented souls who suffered these taunts in the 1950s and 60s would be the harbingers of the sexy look of the '70s and '80s -- the bald look? Certainly not Redd Foxx, Louis Gossett Jr., Issac Hayes, Telly Savalas or Yul Brynner."

The Jet can start or enliven a conversation anywhere, carrying over into print the oral tradition of taletelling in the old black barbershop. Benjamin Saulter, a Washington attorney, says: "On my coffee table at home, I have Jet, the Washingtonian, Time, others. Inevitably my black guests pick up The Jet first. Generally they don't buy or subscribe or admit to reading it but they pick it up and cherish it."

The Jet was started in 1951 with a mandate of advocacy and morale boosting: to entertain and inform a black readership at once bypassed and typecast by the major media. Over the years it has avoided criticism of controversial black politicians, such as Adam Clayton Powell and Charles Diggs, and has promoted the careers of entertainers from Lola Folana to Lionel Ritchie. Among its favorite stars has been Diahann Carroll, a perennial who was once the subject of an article titled "I've Been Black All the Time."

The Jet's success, its critics feel, should encourage the magazine to be more socially responsible. One complaint: in recent years a quadraplegic mother who changes diapers with her teeth and tongue has gotten more space than any of Ronald Dellums' statements on military spending or Parren Mitchell's hearings on black minority business.

Answering that criticism The Jet's editors and reporters stress the cold fact that serious subject covers reduce the lucrative newsstand sales.

"Typical was the attitude toward Johnny Ford, the mayor of Tuskegee," says former Jet reporter Warren Brown. "There was a real story in his relationship with George Wallace. But publisher John Johnson wanted emphasis on Ford's relationship with his white wife. So we did a cover on his family and '60 Minutes' did the other story. To Johnson's credit we went hard on the Tuskegee syphilis story, but we were reminded constantly that sales went down when the cover was hard news."

The Jet's steady preference for soft news over breaking events doesn't bother Ronn Nichols, director of media services for the Congressional Black Caucus. "No question, it's useful," says Nichols. "That's my major source when I need to get something out there."

While The Jet may not grace many covers with the faces of black politicians, black politics is very much in evidence. In its coverage of the Reagan inaugural parties, for example, the magazine ran pictures of almost every black guest, with copy that began, "It was the whitest inauguration in years -- without snow."

And on the 25th anniversary of the Supreme Court decision outlawing school segregation, an article started: "It's ironic that, today, white people are whining about the evils of busing children to integrated schools. They, or perhaps their parents, didn't complain when a 7-year-old black girl who lived three blocks from a school in Topeka, Kan., had to travel 21 blocks so that the school could remain lily-white."

Quirky traditions abound in The Jet: many funeral stories have a photograph of the open casket, including a recent one of Roy Wilkins. Some of The Jet's most grisly layouts included photographs of the murdered youth, Emmett Till; singer Otis Redding frozen and strapped into his airplane; the man propped up in his casket because his parents didn't want him to die "lying down."

Each issue offers such standard features as snapshots of interracial couples or black-white business-political partnering. Visual integration is always prominently displayed; where once Ross Barnett and Constance Baker Motley were featured, now there's Jane Byrne with Maynard Jackson, Ronald Reagan with Shehu Shagari. Another cornerstone is The Jet Centerfold, a full-page color photo of a young woman in a swimsuit, accompanied by a one-line description of her physical assests and professional ambitions. There is sure to be a promotion through a story, photographs or advertisment of the products and family of editor and publisher John H. Johnson, founder of The Jet and its sister magazine, Ebony.

The oddities of life always get a ride, such as the identical twins born to a mixed couple in Britian, one girl blue-eyed and fair, the other brown-eyed and darker. This year's one-handed boxer had a direct predecessor in The Jet's 1957 one-armed golfer. What's more, The Jet's editors often follow up on those stories. This year, for example, they looked in on how a baby believed frozen in 1956 had grown up.

The magazine and many of its subjects are generally quotable. This from the November 1978 column of "People Are Talking About. . .": "Why the irrepressible Rev. Ike is bothered by inflation. Rev. Ike says that his consciousness of wealth keeps him above the fluctuations in the economy. Said Rev. Ike, 'Money just seems to come to me. Rolls Royces are drawn to me in the same way.' And you thought there was a trick."

In the little-known world of black publishing, only a few of the 250 magazines reach a sizable audience. Of those, The Jet is the most egalitarian, reaching for Everyman, while Ebony, Essence and Black Enterprise reach for the more specialized, more established achiever. The Chicago-based Johnson Publications has had few of the economic problems of other black magazines, but it has trimmed its editorial roster recently, suspending in 1976 a serious black journal, Black World, and this year dropping Black Stars.

The Jet, however, was the pacesetter. Its early concentration on the issues of equal rights, the pioneering efforts of Thurgood Marshall, Ralph Bunche and Nat King Cole, created a civil rights beat long before other media caught on to Birmingham. But this journalistic and social agenda often fell second to the ridiculous, so much so that television producer Charles Hobson, who grew up in New York in the 1950s, remembers hiding The Jet inside another magazine on the subway. If asked for his source of information by a white he would say, with a French accent, "The Tej" -- The Jet, spelled backwards.

Simeon Booker, the company's Washington bureau chief, recalls how they got the photograph of Emmett Till's body in 1955 that pushed sales over the half-million mark and prompted the first of three reprints in Jet's history. (The others were the deaths of Nat Cole and Martin Luther King Jr.) " Till's battered body had been shipped in a bag up to a Chicago funeral home. The photographer and I went over to the funeral parlor and while we were taking pictures, the top of his skull fell off. That's how bad he had been beaten," said Booker. For many blacks that photograph intensified their anger and gave grass-roots support to the burgeoning civil rights movement.

In the 1960s The Jet's natural constituency became the major stories of the decade, and the magazine found itself paving the way as well as competing. Like many members of the media at the time, Jet's reporters placed their lives on the line. Larry Still, a journalism professor at Howard University, was one of The Jet stalwarts. "When we were covering James Meredith," Still recalled, "Ernest Withers, the photographer, and myself, caught up with him, and he turned around and said, 'Are you all right? I was worried about you, I have protection.' " Later, The Jet investigated the inequities suffered by blacks fighting the war in Vietnam, sending Simeon Booker out on two field trips, and conducted a survey of its readers to find whether they preferred to be called "Black" or "Negro."

Then, as now, The Jet was often part of the news. Robert Johnson, the associate publisher and executive editor, recalls a story about a black man sentenced to die for a $1.95 burglary in Alabama that Johnson says made John Foster Dulles, then secretary of state, intercede for the man's life. The Jet forced the integration of the White House photographers' associations. When Martin Luther King was jailed in Atlanta during the 1960 presidential campaign, his family called The Jet's office in Washington to see if they could get some reaction from the White House. Larry Still was traveling with then-vice president Richard Nixon, and went right to him for a comment. "He said it was a states' rights issue. He didn't intercede but the next day John Kennedy did," says Still.

In the 1970s, when major stories were the rise of black political power and the erosion of the gains of the 1960s, The Jet stuck to its celebrity covers. One issue had Tina Turner on the cover, while the stories of the Attica prison uprising and the effects of Nixonomics were inside. Yet one former editor, Bill Berry, remembers two serious covers in the early 1970s -- one on black crime and the other on drugs in the black community -- being runaway best sellers for their years. Robert Johnson offers his philosophy: "We have discovered it isn't so much the message but the messenger . . . Almost every leader has talked about pride and culture. Then James Brown comes along and says, 'Say it loud, I am black and proud.' We talk to Michael Jackson about his source of inspiration. And he says, 'When I am through I go home to my favorite place, the library, and read.' Now some librarian read that story and made a book marker with his quote."

While the emphasis had shifted, Simeon Booker's "Ticker Tape U.S.A." column continued to prod the White House about black issues. "During the Nixon administration I put a little note that the White House was looking for black secretaries. They were flooded with applications and called and gave me hell. I said, 'Oh, hell, now you can hire one,' " recalls a laughing Booker. While the magazine did ask 150 black legal experts what they thought of Watergate, they spent a disproportionate amount of space chronicling the singing Jacksons from bubble gum to Bentleys.

In the 1980s, The Jet continues to provide the black angle on major and minor news events. Where else could readers get every detail and follow-up on the life of the one black held hostage for the entire ordeal in Iran, Charles Jones Jr.? Or an interview with Jimmy Carter that emphasizes civil rights? The magazine still pursues the big racial stories like the national spree of racially motivated murders last year, and often has a motivation story, such as the 11-year-old computer whiz. And, of course, the magazine could be counted on to reveal the identity of the black man who sat next to Nancy Reagan at last summer's British royal wedding.

But sometimes The Jet reaches too far. Last year Booker noticed that a White House photograph of Jimmy Carter had a blacked-out face behind the president. Booker jumped to the conclusion it was Louis Martin, a black White House aide. It turned out to be a New York Times reporter.

The Jet's editors believe the magazine has not outlived its original purpose. Robert Johnson says the responsiblity hasn't dimmed. Uplifting is still a necessary goal. Says Johnson, "Are we building a case for blacks? . . . Some blacks still believe that the white man's water is wetter, that his ice is colder."