LOS ANGELES - Don Knotts, who kept generations of TV audiences laughing as bumbling Deputy Barney Fife on "The Andy Griffith Show" and would-be swinger landlord Ralph Furley on "Three's Company," has died. He was 81. Knotts died Friday night of pulmonary and respiratory complications at the University of California, Los Angeles Medical Center, said Sherwin Bash, his friend and manager. Griffith, who had visited Knotts in the hospital before his death, said his longtime friend had a brilliant comedic mind and wrote some of the show's best scenes. "Don was a small man ... but everything else about him was large: his mind, his expressions," Griffith told The Associated Press on Saturday. "Don was special. There's nobody like him. "I loved him very much," Griffith added. "We had a long and wonderful life together." Unspecified health problems had forced Knotts to cancel an appearance in his native Morgantown, W.Va., in August. The actor's half-century career included seven TV series and more than 25 films, but it was the Griffith show that brought him TV immortality and five Emmys. The show ran from 1960-68, and was in the top 10 of the Nielsen ratings each season, including a No. 1 ranking its final year. It is one of only three series in TV history to bow out at the top: The others are "I Love Lucy" and "Seinfeld." The 249 episodes have appeared frequently in reruns and have spawned a large, active network of fan clubs. As the bug-eyed deputy to Griffith, Knotts carried in his shirt pocket the one bullet he was allowed after shooting himself in the foot. The constant fumbling, a recurring sight gag, was typical of his self-deprecating humor. Knotts, whose shy, soft-spoken manner was unlike his high-strung characters, once said he was most proud of the Fife character and doesn't mind being remembered that way. His favorite episodes, he said, were "The Pickle Story," where Aunt Bee makes pickles no one can eat, and "Barney and the Choir," where no one can stop him from singing. "I can't sing. It makes me sad that I can't sing or dance well enough to be in a musical, but I'm just not talented in that way," he lamented. "It's one of my weaknesses." Knotts appeared on several other television shows. In 1979, he joined the cast of "Three's Company," also starring John Ritter, Suzanne Somers and Joyce DeWitt. Early in his TV career, he was one of the original cast members of "The Steve Allen Show," the comedy-variety show that ran from 1956-61. He was one of a group of memorable comics backing Allen that included Louis Nye, Tom Poston and Bill "Jose Jimenez" Dana. Knotts' G-rated films were family fun, not box-office blockbusters. In most, he ends up the hero and gets the girl — a girl who can see through his nervousness to the heart of gold. In the part-animated 1964 film "The Incredible Mr. Limpet," Knotts played a meek clerk who turns into a fish after he is rejected by the Navy. When it was announced in 1998 that Jim Carrey would star in a "Limpet" remake, Knotts responded: "I'm just flattered that someone of Carrey's caliber is remaking something I did. Now, if someone else did Barney Fife, THAT would be different." In the 1967 film "The Reluctant Astronaut," co-starring Leslie Nielsen, Knotts' father enrolls his wimpy son — operator of a Kiddieland rocket ride — in NASA's space program. Knotts poses as a famous astronaut to the joy of his parents and hometown but is eventually exposed for what he really is, a janitor so terrified of heights he refuses to ride an airplane. In the 1969 film "The Love God?," he was a geeky bird-watcher who is duped into becoming publisher of a naughty men's magazine and then becomes a national sex symbol. Eventually, he comes to his senses, leaves the big city and marries the sweet girl next door. He was among an army of comedians from Buster Keaton to Jonathan Winters to liven up the 1963 megacomedy "It's A Mad, Mad, Mad, Mad World." Other films include "The Ghost and Mr. Chicken" (1966); "The Shakiest Gun in the West" (1968); and a few Disney films such as "The Apple Dumpling Gang" (1974); "Gus" (1976); and "Herbie Goes to Monte Carlo" (1977). In 1998, he had a key role in the back-to-the-past movie "Pleasantville," playing a folksy television repairman whose supercharged remote control sends a teen boy and his sister into a TV sitcom past. Knotts began his show biz career even before he graduated from high school, performing as a ventriloquist at local clubs and churches. He majored in speech at West Virginia University, then took off for the big city. "I went to New York cold. On a $100 bill. Bummed a ride," he recalled in a visit to his hometown of Morgantown, where city officials renamed a street for him in 1998. Within six months, Knotts had taken a job on a radio Western called "Bobby Benson and the B-Bar-B Riders," playing a wisecracking, know-it-all handyman. He stayed with it for five years, then came his series TV debut on "The Steve Allen Show." He married Kay Metz in 1948, the year he graduated from college. The couple had two children before divorcing in 1969. Knotts later married, then divorced Lara Lee Szuchna. In recent years, he said he had no plans to retire, traveling with theater productions and appearing in print and TV ads for Kodiak pressure treated wood. The world laughed at Knotts, but it also laughed with him. He treasured his comedic roles and could point to only one role that wasn't funny, a brief stint on the daytime drama "Search for Tomorrow." "That's the only serious thing I've done. I don't miss that," Knotts said. ___ Associated Press writer Vicki Smith in Morgantown, W.Va., contributed to this report.