At the end of 1939, Frank Sinatra left the Harry James Orchestra to join the Tommy Dorsey Orchestra, where he rose to fame as a ballad singer. His first and biggest hit with the band was 1940s "I'll Never Smile Again," which spent several weeks at number one - and was the first "number one" - on Billboard magazine's then-new chart of America's top-selling records. His vast appeal to the "bobby soxers," as teenage girls were called, revealed a whole new audience for popular music, which had appealed mainly to adults up to that time. Read more on Last.fm