Come fall, nobody is going to step out of the shower and tell us it was all a dream. After 13 years and 356 episodes, "Dallas" is closing down the ranch with a two-hour episode tonight (8 p.m., Ch. 5).

And there's no mystery about "Who killed J.R. and Company." 'Twas poor ratings did the deed.Never lauded as great drama by the critics, "Dallas" nonetheless became one of the most successful series in television history. (Only "Gunsmoke" produced more episodes than the 356 churned out by the Ewings.) For the first half of the '80s, the show was never out of the Nielsen Top 10, finishing first in 1980-81, 1981-82 and 1983-84.

The series' most famous episode came Nov. 11 1983, when the audience learned the answer to the question "Who Shot J.R.?" More than 80 million Americans tuned in - 77 percent of the available audience.

At the time, it was the most-watched episode in television history. And it's only been surpassed by the finale of "M*A*S*H."

But the season-ending cliffhanger that "Dallas" popularized has reached far beyond the soap opera genre. These days, all kinds of shows end their seasons by leaving the audience in suspense - everything from "Cheers" to "Night Court," "Murphy Brown" to "Star Trek: The Next Generation."

The show also became an international phenomenon, airing in more than 90 countries and becoming wildly popular in dozens of them. And carrying a rather interesting view of America along with it.

But "Dallas" was more than just a television show, it became a cultural phenomenon. Debuting as a spring series in May 1978 with just five episodes, it was a hallmark of the Reagan years, when greed was good and excess stylish.

And J.R. (Larry Hagman) became a symbol for the '80s. Not really a classic villain - he wasn't evil for evil's sake - the oldest Ewing brother was a practitioner of rampant self-interest. (And he extended his "self" to include his beloved Ewing Oil.)

J.R. didn't let anyone or anything stand in the way of his drive for success, whether it was financial success or personal success. Not marriage. Not family. Not business partners. Not the legal system.

At the same time, J.R had a strong sense of family. He wanted to please his Daddy, build a legacy for his son, and he loved his other relatives - although he wasn't above smiting them down if they got in the way.

"Dallas" was built on many familiar themes. Good (Bobby) vs. evil (J.R.). Rural (ranching) vs. urban (the dirty oil business). A classic family feud - Ewings vs. Barnes - that hearkened back to the Hatfields and the McCoys and even the Montagues and the Capulets. Bobby Ewing (Patrick Duffy) did marry Pamela Barnes (Victoria Principal), after all.

As a matter of fact, "Dallas" creator David Jacobs said he was inspired by a pair of plays - "Romeo and Juliet" and "Cat On a Hot Tin Roof."

Although it's a fact now almost lost in television history, "Dallas" did not begin as a serial. Early episodes were self-contained.

It wasn't until Sue Ellen (Linda Gray) became pregnant and the child's paternity was questionable (it turned out to be J.R., not Cliff, who was the father) that the stories began to stretch out over weeks and months."Dallas" was also not the show it started out to be. As originally conceived, Pamela Barnes Ewing was the main character. J.R. was secondary, and Sue Ellen wasn't even in the opening credits.

The producers even planned to kill Bobby off after the first six episodes, leaving Pam to battle for her rightful place in the Ewing dynasty.

And what a dynasty it was. The Ewing Saga extended back more than 40 years, when partners Jock Ewing (Jim Davis) and Digger Barnes (first David Wayne, then Keenan Wynn) were oil wildcatting partners and rivals for the affections of Ellie Southworth (Barbara Bel Geddes). Their falling out led to decades of feuding, which was passed on to sons J.R. and Cliff (Ken Kercheval).

The story of Jock, Digger and Miss Ellie was even made into a 3-hour, made-for-TV movie ("Dallas: The Early Years") that drew big ratings.

"Dallas" was always full of larger-than-life characters, fighting, feuding and loving their way through kidnappings, takeovers, embezzlement, murder, adultery, death and disease. Sometimes the plots were enormously dumb - Bobby returning from the dead after Pam "dreamed" a whole season leads the list.

But while the core cast remained, the tried-and-true machinations worked. It wasn't until cast members like Gray, Principal and Kanaly left that "Dallas" started running out of steam.

The plots became increasingly repetitive and ratings sagged. As a matter of fact, had CBS not experienced all kinds of ratings troubles the past few seasons, "Dallas" probably would have ended two or three years ago.

But while tonight's finale is billed as THE END, don't you believe it. With all the members of the younger generation who've been produced over the seasons, here's betting we'll see a revival of the Ewing Saga sometime down the road.


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Last chance to catch up on J.R.'s `wonderful' life

For those of you who haven't been keeping up with "Dallas" lately, here's the current situation:

J.R. has been through a series of personal crises. His mother gave the ranch to brother Bobby. His second wife left him, taking his infant son. His oldest son just left town along with J.R.'s only grandchild. Son John Ross left Dallas to live with his mother in London.

Tricked into believing he would be the next chairman of oil giant Weststar, J.R. sold his half of Ewing Oil to longtime rival Cliff Barnes. And then he found out about the trick.

The poor guy even lost his longtime secretary.

So when we left him last week, J.R. was sitting with a gun in his hand, contemplating suicide.

Tonight's two-hour finale is a takeoff on "It's a Wonderful Life." Guest star Joel Grey appears as an angel, showing J.R. what life would have been like if he'd never been born.

In addition to current cast members, former stars Linda Gray, Steve Kanaly, Mary Crosby, Jack Scalia and "Knots Landing" stars Ted Shackelford and Joan Van Ark are woven into the plot.