Before Dave or Jay or even Johnny there was Steve Allen. Much of what is now called talk television can be directly traced to the man who created the "Tonight" show on NBC in 1954. And anyone who doubts it need only to drop by the Museum of Television and Radio anytime in the next five months.
Today the museum begins a retrospective of Mr. Allen's broadcasting career, which has spanned more than four decades. The volume of Mr. Allen's work is extraordinary, and so is the impression it leaves on those who plumb it, said the museum's television curator, David Bushman.
"Almost all of the conventions of what we have come to know as the talk show are there, from the opening monologue to the banter with the band leader to the regular characters in sketches," Mr. Bushman said of Mr. Allen's four-year reign on the show. Creating and Breaking the Rules
It is less well known, Mr. Bushman added, that Mr. Allen also helped pave the way for Oprah, Phil and Geraldo. For example, one night early in his career Mr. Allen broke with his entertainment format and did an entire 90-minute show on organized crime. Another time, Mr. Allen decided to demonstrate what happens to people who try to drive after they drink. He consumed six double vodkas in the course of the show, reducing himself to giddy embarrassment.
He also did theme shows with guests like "sons of famous men" and "wives of famous comedians." Such things turn up today in listings of what's on Sally or Montel.
Mr. Allen himself has not been reluctant to point out that much of what Johnny Carson did in his 30-year tenure on "Tonight" and even what David Letterman and Jay Leno do on late-night television has its roots in what Mr. Allen and his cast of characters did. Seen in the vintage tapes and kinescopes collected by the museum, Mr. Bushman said, the lineage is unmistakable. Jell-O and Other Treats
A short clip from one of Mr. Allen's most famous bits, "The Question Man," makes it clear where Mr. Carson's far more famous "Carnac the Magnificent" routine came from. Mr. Letterman has acknowledged his debt to Mr. Allen's stunt humor; during the retrospective one can see Mr. Allen rolling around in a giant bowl of tossed salad with a female wrestler or jumping into a vat of Jell-O. (If you catch the right rerun of Mr. Letterman's show on cable, you will see him sticking himself to a wall in a Velcro costume or dropping into a bowl of milk while covered in Rice Krispies.)
Mr. Allen, now 72, is to attend the two special seminars today, which kick off the retrospective at the museum, at 25 West 52d Street. (Both are sold out.) In an interview yesterday at the Park Avenue apartment of the actress Audrey Meadows, the sister of Mr. Allen's wife, Jayne, Mr. Allen, who is mildly hobbled by a case of sciatica and has exchanged his trademark black-framed glasses for a tortoise-shell look, said he was extremely pleased by the effort by the museum in assembling the five-month series of programs.
"I'm amazed that they went to so much trouble," Mr. Allen said.
But he said he didn't see the creation of the realm of late-night television as the crowning artistic achievement of his career.
"I see where it was important in one context," he said. "But if you evaluate it in the context of the great tapestry of Western ideas. . . ." That very thought evokes peals of the familiar, infectious Allen laugh.
The metaphor Mr. Allen prefers for conveying the importance of the "Tonight" show is the paper towel.
"They are very useful objects," he said of paper towels. "Otherwise we'd be drying our hands on our shirts. But compared to a great opera? The talk show is garbage compared to that level of achievement."
Still, he acknowledged with pride that his old show made a lot of people laugh. "It was the second-best sketch-comedy show in the history of television," he said, trailing only Sid Caesar's "Your Show of Shows." The First Show
Unfortunately, the museum's retrospective cannot fully document that level of excellence. The program does include the first "Tonight" show, on Sept. 27, 1954 (guests included Wally Cox and Willie Mays), to be shown on Friday at 12:15 P.M., as well as compilations of highlights on other dates. (Among the memorable moments: Mr. Allen's famous routine of reading aloud, with a great show of emotion, letters to the editor of The Daily News and impromptu comedy derived from interviews with people on the street outside his old Hudson Theater, another routine that presaged Mr. Letterman's exchanges with his Broadway neighbors.)
But very few of Mr. Allen's four years on "Tonight" have survived what he called "a cultural atrocity." An NBC employee in the late 1950's made a decision to clear space by burning up tapes of old programs stored in New Jersey. Mr. Allen said every one of his "Tonight" shows stored there was lost. The few that survive -- he said he has only about 25 -- come from other sources.
Some classic programs are gone forever, Mr. Allen said, including a 90-minute interview with Carl Sandburg and an entire show with Richard Rodgers around the piano.
The bulk of the museum programs consist of Mr. Allen's post-"Tonight" work: his Sunday night variety show on NBC (which included the first "man in the street" routine, a comedy bit with Elvis Presley before he sang from the waist up for Ed Sullivan and a memorable night when the Three Stooges followed Lenny Bruce as guests); his later syndicated shows for Westinghouse (where a very young Woody Allen performed stand-up comedy), and Golden West Broadcasting (where Steve Martin joined the men in the street).
Also included are many television interviews of Mr. Allen, with Edward R. Murrow and Mike Wallace among others, some of Mr. Allen's early radio work and one full program based on his PBS series "Meeting of Minds," in which actors portraying great thinkers and other figures of history gathered in a talk-show format (and won a Peabody Award in the process.)
Mr. Bushman said his research into Mr. Allen's career, which has also included an enormous body of musical work and the publication of more than 40 books, revealed a man "of conflicting artistic sensibilities." Mr. Bushman called Mr. Allen "a man with two sides: the serious man trapped in a vaudevillian's body."
Photo: A retrospective of the career of Steve Allen begins today at the Museum of Television and Radio.