When ESPN went on the air Sept. 7, 1979, the all-sports cable network was little more than a novelty for most fans. Eight years later, ESPN has become a necessity for most fans.

From Australian Rules Football to the National Football League, it has been a remarkable road for the Bristol, Conn.-based company. And, although its ground-breaking NFL contract unquestionably gave ESPN the crowning jewel in its schedule, ESPN had been accelerating toward major status well before that deal was completed.

But it is the NFL telecasts -- the first on cable, with eight regular season games over each of the next three years -- that has transformed the public's perception of the 24-hour sports network.

"They were the be-all and end-all of sports when they first came on," said Jon Mandel of Grey Advertising Agency in New York, "but they needed something big time. They had hockey, but what other professional sports did they have? What was on ESPN? Just a bunch of car races, women's billiards and Australian football.

"So the NFL brought them to the big time."

Although some of ESPN's schedule always has been easy to belittle -- roller derby, skateboarding and tractor pulls -- it still has compiled a heavyweight lineup even without the NFL's addition.

Among the items on ESPN's regular menu: college basketball, including early rounds of the NCAA tournament; college football; golf, including early rounds of three Grand Slam tournaments; boxing; tennis, including the Davis Cup; the NHL, including the Stanley Cup; MISL soccer; bowling; auto racing and horse racing. It also televises the America's Cup, the U.S. Olympic Festival, the Boston Marathon and the College World Series.

Also, ESPN's flagship studio program, "SportsCenter," has become a nightly must for sports junkies, providing far more extensive sports coverage than local newscasts.

Aside from having the higher-profile events, ESPN is a repository for such limited-audience pursuits as running, surfing and aerobics.

"We're like a special-interest magazine," said ESPN President Bill Grimes, "and we cater to all type of special interests. We like the diversity of our mix."

Grimes, along with executive vice president Roger Werner, has been the steward through ESPN's boom period. Grimes, 46, came to ESPN in October 1981 after spending 13 years at CBS and became ESPN's president in June 1982.

Started by a group that included Getty Oil Co., ESPN was sold to ABC in 1983. Capital Cities/ABC now owns 80 percent and Nabisco (a unit of R.J. Reynolds) owns the remaining 20 percent.

ESPN's financial road to the NFL has been rocky. It has gone through three ownership changes and years of mounting losses. Many of its productions were of low quality. Recently, it stumbled when the U.S. Football League was a bust.

But the financial picture has brightened considerably recently.

ABC's 1983 purchase of ESPN was for a reported $202 million. ESPN's current market value might be five times that. In '85, ESPN showed its first operating profit -- about $1 million. In '86, profits reportedly rose to $40 million. In 1987, ESPN could earn between $60 million and $75 million, according to analysts at Donaldson, Lufkin & Jenrette Corp. and at First Boston Co.

Grimes and industry observers cite several reasons for ESPN's growth: The 1983 decision to charge cable operators a fee to carry ESPN. In January 1984, the cost was 13 cents per subscriber per month; now, it's 27 cents. That has provided critical revenue in addition to advertising dollars. The continued wiring of America. When ESPN first went to a 24-hour-a-day schedule, it was carried in only 4.7 million homes; now, the figure is 43.7 million, representing half of the television homes in the United States. Stronger event programming, with fewer repeat broadcasts of games. In 1980, ESPN had 1,800 hours of live, original programming; in 1987, that figure will be more than 3,700 hours.

ESPN's advertising revenue, Grimes said, "grew 20 percent each year in 1984, 1985 and 1986 while the networks were growing only by 2 or 3 percent." (Of course, ESPN is only taking a tiny piece out of that network pie.) From its inception, ESPN has been buoyed largely by Anheuser-Busch's strong ad support -- $1.4 million when ESPN debuted, a five-year, $25 million commitment in October 1980 and then a five-year, $70 million commitment in November 1985.

The addition of the NFL should enhance ESPN's overall advertising outlook.

"They needed something big to legitimize themselves, and the NFL's the clincher," said Steven Grubbs of BBDO agency in New York. "It changes the whole approach to Sunday nights from an advertiser's standpoint. Between Fox and ESPN, you're going to see much lower viewing levels on the network.

"It also enables ESPN to package the NFL with other properties they might have trouble selling."

Smaller sports are difficult ad sells for ESPN. But something like bowling is relatively inexpensive to produce. Thus, ESPN is at a minimal risk.

In addition, ESPN does a lot of business with programming, such as "The Fishing Hole," that is packaged and produced by independent groups. Those low-rated shows, Grimes said, "are guaranteed profit going in" because ESPN does not have production costs and because it benefits from the producers' advertising contacts in each specialized field.

Ironically, it was one specialized, seemingly low-interest sport -- yachting -- that accelerated ESPN's national clout and helped it land the NFL contract. ESPN's America's Cup coverage earlier this year was widely lauded.

"The critical acclaim for our America's Cup coverage," Grimes said, "did more than anything in our history in making us perceived as television, not just cable TV . . . I remember a conversation at the time with {NFL Commissioner Pete} Rozelle, telling him we'd really arrived. It sent a message out and heightened the awareness of us immeasurably."

It is that type of programming risk -- exemplified again this past summer with Arena Football -- that most easily separates ESPN from network sports departments.

"Networks are less willing to take as many chances," said NBC Sports' executive producer, Michael Weisman. "It's almost as if ESPN is off-Broadway for a lot of sports. They play ESPN first, and if it works there, bring it to the networks. Take yachting. Before ESPN did the America's Cup, we weren't planning to do much yachting at the '88 Olympics. Now we are."

ESPN paid $153 million for its three-year NFL package. For a network that produces less than $100 million annually in advertising revenues, that cost might seem prohibitive. But ESPN scored another first in landing the NFL -- getting cable operators to pay an added 9.5 cents per subscriber per month to participate in the football telecasts. And nearly all of ESPN's 17,000 cable-system affiliates signed up.

"It's been clear to us that the cable operators wanted to acquire some high-marquee, mass-appeal programming for some time," Grimes said.

Grimes reasoned to cable operators that the NFL would help retain and add subscribers and that, with ESPN doubling the amount of advertising time the systems could sell, "it would really put them in the local ad sales market for the first time."

With ESPN's NFL preseason games getting the biggest sports ratings in cable history, ESPN is eager to see what its regular season package, which debuts with the New England Patriots-New York Giants game Nov. 8, will do.

Beyond the NFL, ESPN now is looking toward other plums. "Only a few things elude us," Grimes said.

Among those things are major league baseball and the NBA. Before the most recent NFL contract was signed, network executives scoffed at the possibility of cable getting a part of the deal. But the skepticism is ending. "I'd be shocked if ESPN wasn't involved with baseball in 1990," said a CBS Sports executive who asked not to be named.

"Down the road," Grubbs said, "you'll see ESPN get a piece of the baseball contract and they'll be a much stronger contender when the NBA contract is up for renewal."

Baseball's contract with NBC and ABC runs through 1989, as does the NBA's contract with CBS and WTBS, ESPN's biggest rival for cable sports rights.

Said Weisman: "ESPN has become a major force in the sports scene."

"My dream," Grimes said, "would be to have the entire NCAA basketball tournament on ESPN. Maybe that's just a dream."

Maybe it is. But who's to say about a network that debuted with coverage of the slow-pitch softball championships and is showing NFL football less than 100 months later?