On Sept. 10, 1955, cast members of a new television show gathered to watch the first episode. Much to their surprise, legendary actor John Wayne came on to introduce the program.

"I've made a lot of pictures," Wayne said onscreen, "some of them have been Westerns . . . and that's why I'm here to tell you about tonight . . . a new television show called 'Gunsmoke.' "

Then Wayne introduced the show's star, James Arness. "He's a young fellow, and maybe new to some of you. I predict he'll be a big star."

No one at the time — the cast members included — knew how right that prediction would be, said Ben Costello, author of a new book, "Gunsmoke: An American Institution."

" 'Gunsmoke' became the biggest show of its day — and its day ran a total of 20 years," said Costello.

There were already plenty of Westerns on TV at the time, with such cowboys as Hopalong Cassidy, the Lone Ranger and Roy Rogers sharing adventures. "But most of these were geared to younger audiences," said Costello. " 'Gunsmoke' was the first Western drama to appeal to a more adult audience."

There was plenty of action, but there was also introspection. Arness's character, Marshal Dillon had to think his way out of problems as much as shoot his way out. Storylines revolved around each of the other regular cast members, and a wide variety of guest stars brought fresh angles to the stories.

There's never been another show quite like it, said Robert Houston, executive director of Kanab's Western Legends Round-up, which will be paying a special tribute to "Gunsmoke" in honor of the 50th anniversary of the show's beginning.

"The baby-boomer generation grew up with 'Gunsmoke.' " said Houston. "That's where we learned about the Old West. But it's also where we learned about values. Families watched it together. It was a big part of their lives."

At the Kanab fest, which runs Aug. 23-28, Costello will be introducing his book, which will be hot off the press (Call toll-free 866-471-0777 to find where else it will be available). And Buck Taylor, who played Newly O'Brien for eight seasons, will be in attendance, as will Morgan Woodward and Jan Shepard, who made frequent guest appearances on the show.

Many of the "Gunsmoke" episodes were filmed in Kanab, so it's a natural for Western Legends to observe its 50th anniversary, said Houston. "We're really happy to honor it. It's part of our Western heritage and our film heritage, for Kanab and all of Utah."

People are coming from all over the world for the celebration, he said. The show still has fans — and fan clubs — all over. "The Trekkies have nothing on these guys."