How many decades has the career spanned of the musician who was commissioned to write music for NBC's national news programs
six decades
Title: John Williams
Passage: John Towner Williams (born February 8, 1932) is an American composer, conductor, and pianist.  With a career spanning over six decades, he has composed some of the most popular and recognizable film scores in cinematic history, including "Jaws", the "Star Wars" series, "Close Encounters of the Third Kind", "Superman", "E.T. the Extra-Terrestrial", the "Indiana Jones" series, the first two "Home Alone" films, the first two "Jurassic Park" films, "Schindler's List", and the first three "Harry Potter" films.  Williams has been associated with director Steven Spielberg since 1974, composing music for all but three of his feature films.  Other notable works by Williams include theme music for the Olympic Games, "NBC Sunday Night Football", "The Mission" theme used by NBC News, the television series "Lost in Space" and "Land of the Giants", and the incidental music for the first season of "Gilligan's Island".  Williams has also composed numerous classical concertos and other works for orchestral ensembles and solo instruments.  From 1980 to 1993, he served as the Boston Pops' principal conductor, and is now the orchestra's laureate conductor.
Title: The Mission (theme music)
Passage: "The Mission" is a television news music package composed by John Williams in 1985.  Originally commissioned for NBC's national news programs, the theme has also been used on some NBC affiliates for their local newscasts.
Title: Tom Brokaw
Passage: Thomas John Brokaw ( ; born February 6, 1940) is an American television journalist and author, best known for being the anchor and managing editor of "NBC Nightly News" for 22 years from 1982 to 2004.  He is the only person to have hosted all three major NBC News programs: "The Today Show", "NBC Nightly News", and, briefly, "Meet the Press".  He now serves as a Special Correspondent for NBC News and works on documentaries for other outlets.
John Williams The Mission (theme music)