With more than 15,000 hours, Downs was the longtime holder of the Guinness World Record for most hours on TV, until Regis Philbin surpassed him in 2004. Downs, who died Wednesday at his home in Scottsdale, Arizona, was the announcer and sidekick on Jack Paar's Tonight Show in the late 1950s and early 1960s. From 1958 to 1969, he was host of NBC game show Concentration. From 1962 to 1971, he co-hosted NBC's Today. And from 1978 to 1999, he co-hosted 20/20 on ABC. Downs "was one of the most versatile and durable personalities on television," says Emily Langer. His 1986 memoir was titled On Camera: My 10,000 Hours on Television. Ron Simon, curator for television and radio at the Paley Center for Media in New York, adds that Downs "represented the entire history of broadcasting. Whatever the format, he was that consummate, quintessential broadcaster who could adapt his style to what was needed." It was Downs who noticed Barbara Walters' talent when she was a Today writer, helping to propel her to "Today girl." They would reteam on 20/20, starting in 1979 as a correspondent as as co-anchor in 1984. “Hugh and I had different personalities and different styles, yet we complemented each other,” Walters wrote in her 2008 memoir Audition. “He was more contemplative and thought of himself as something of a philosopher. His questions during interviews were gentler than mine, but he never restricted me from asking what I wanted. In short, he was . . . one of the truest gentlemen I have ever known.” Downs was born in Akron, Ohio in 1921. After serving in the U.S. Army in World War II, he joined NBC's radio affiliate in Chicago. He got into TV in the early 1950s working on a puppet show. His first prominent gig was as an announcer and sometimes performer on Sid Caesar's Caesar's Hour during its final year in 1956-57, working with Carl Reiner, who died Monday at age 98. In 1958, he joined Paar's Tonight Show. At first, only Downs’ voice was heard on the show, but soon, “after I had done the announcing, (Paar) would, out of loneliness, I guess, ask me to come over,” he recalled in a 1997 Archive of American Television interview. “He would occasionally have some question and turn to me for the answer. He began to call me ‘a walking encyclopedia.’ Red Skelton said later, 'Hugh Downs in the kind of guy who when you ask him what time it is, he tells you how to build a watch.'" Downs guest-hosted The Tonight Show more than anybody else during Paar's reign, including when Paar walked off the show in 1960. So Downs expected he would get The Tonight Show hosting job when it became available in 1962. Instead, The Tonight Show went to Johnny Carson, while he was offered the Today show.