DeForest Kelley, 79, an actor best known to millions of Trekkers, Trekkies and television viewers as Dr. Leonard "Bones" McCoy, the crusty and cantankerous Georgia native who sailed aboard starships named Enterprise in seemingly countless "Star Trek" films and television episodes, died June 11 at a hospital in Woodland Hills, Calif.

A spokesman for the Motion Picture and Television Country Home and Hospital said that he died after "an extended illness" but did not reveal the cause of death.

Mr. Kelley projected the persona of a man combining a 23rd-century scientist with that of an old-fashioned country doctor who makes house calls.

He was one of the original stars in the original "Star Trek" series that ran on NBC-TV from 1966 to 1969. The demise and unbelievable rebirth of the series is the stuff of legend.

The show was the brainchild of Gene Roddenberry, a veteran writer of such TV westerns as "Wagon Train" and "Have Gun, Will Travel," who envisioned a sophisticated science fiction series in which a united Earth and other planets were exploring the galaxy.

Roddenberry thought CBS was going to pick up his series in 1965, but the programming experts at that network put their money on "Lost in Space." But NBC picked up his show for 1966.

The show's stars included William Shatner as Capt. James T. Kirk, the ship's dashing commander, and Leonard Nimoy as Mr. Spock, the "Vulcan" first officer who seemed a cross between a human and a computer. Mr. Kelley, as ship's doctor, spent nearly every episode crossing swords with Spock over everything under, well, several suns.

If Spock was the champion of science and pure logic, "Bones" McCoy was an eloquent and impassioned voice for gut instincts, the powers of blind emotions and the strength of humanity itself.

Upon learning of Mr. Kelley's death, Nimoy said of his colleague, "He represented humanity, and it fitted him well. He was a decent, loving, caring partner and will be deeply missed."

The doctor also maintained a close relationship with the captain, often addressing him by his first name, often acting as the captain's sounding board in difficult times and gradually becoming, along with Spock, his closest friend. And as ship's doctor, McCoy was one of the only crew members who could countermand the captain's or Spock's orders -- making for some interesting plots.

The interaction of these three characters came to be treasured by Star Trek fans, and helped carry the series not only through three seasons on NBC, but also into an animated series, scores of Trek novels and a half-dozen immensely popular motion pictures.

Mr. Kelley also reprised his role in a 1987 cameo for the pilot episode of "Star Trek: The Next Generation," a Paramount Television series that took the Star Trek universe a century beyond the original series and ran with immensely high ratings for seven years.

Before "The Next Generation" signed off, Paramount had added "Star Trek: Deep Space Nine," and "Star Trek: Voyager" to its lineup.

Deforest Kelley was born in Atlanta on Jan. 20, 1920. His father was a Baptist minister. The younger Mr. Kelley graduated from high school at age 16. The following year, he left Georgia for the first time to visit an uncle in California. The trip, which was supposed to be for two weeks, ended up lasting a year. Upon returning to Georgia, he told his disappointed family that he had decided to return to California and become an actor.

He did just that.

After appearing in a Navy training film, he started getting regular, if not starring, work in both television and movies. His TV credits included appearances on "The Lone Ranger," "The Millionaire," "Gunsmoke," "Trackdown," "Rawhide," "Wanted: Dead or Alive," "Richard Diamond, Private Eye," "Bat Masterson," "Perry Mason," "Have Gun, Will Travel," "Route 66," and "77 Sunset Strip."

In addition to his six Star Trek films, his 30 movie credits included "Apache Uprising," "Gunfight at the O.K. Corral," "Raintree County," "The Man in the Gray Flannel Suit" and "Taxi."

The Associated Press reported that Mr. Kelley didn't object to being typecast as McCoy.

"He loved it. He loved that series so much," said A.C. Lyles, a friend and longtime Paramount Studios producer who knew Mr. Kelley for five decades.

Lyles recalled that in 1940, Mr. Kelley lost the leading role in "This Gun for Hire" to Alan Ladd. But as a result, he was given a Paramount contract and was promised regular work in Westerns.

"I always used him as a heavy, a mean man, and he was marvelous at that," Lyles told the AP.

Mr. Kelley, who often attended Star Trek conventions, grew roses as a hobby.

Survivors include his wife of nearly 55 years, Carolyn.

CAPTION: DeForest Kelley projected the persona of a 23rd-century scientist combined with an old-fashioned country doctor.