David Letterman is an award-winning American television personality, late night talk show host, television producer, Indy Racing League car owner and philanthropist. His first major success was on the long-running NBC television program ?Late Night with David Letterman?, before he transferred to CBS in 1993 to his current position on ?The Late Show?.
Letterman has garnered both critical and industry praise; his shows have received 89 Emmy Award nominations, winning fourteen times in his first twenty years in late night television. Letterman has been ranked as high as second in the annual Harris Poll of Nation’s Favorite TV Personality.
In December of 2006, CBS announced that David Letterman had signed a new contract to host the Late Show with David Letterman through the fall 2010.
Source - http://en.wikipedia.org/wiki/David_letterman